Illinois is home to an incredible variety of frogs, from the booming calls of bullfrogs echoing across summer ponds to the tiny peeps of chorus frogs heralding spring. These amphibians are vital to the state’s ecosystems — acting as both predator and prey, helping control insects, and serving as indicators of environmental health. In this guide, we’ll explore 20 types of frogs found throughout Illinois, learn how to identify them, understand their habitats and behaviors, and appreciate their unique roles in nature. Whether you’re a nature enthusiast, a backyard observer, or a budding herpetologist, this guide will help you recognize the frogs hopping (and croaking) through the Prairie State.
1. American Bullfrog (Lithobates catesbeianus)
The American Bullfrog is the heavyweight champion of Illinois wetlands — both in size and voice. As the largest frog in North America, adult bullfrogs can grow up to 8 inches long, and their powerful hind legs make them excellent jumpers and swimmers. Their booming “jug-o-rum” call is unmistakable and often heard in midsummer evenings near ponds, lakes, and slow-moving rivers.
Bullfrogs are easily identified by their olive-green to dark brown coloration and a broad head with a large eardrum (tympanum). Males typically have a bright yellow throat during breeding season. Unlike many frog species, bullfrogs lack a dorsolateral fold — a ridge that runs from the eye down the side — which helps distinguish them from the slightly smaller Green Frog.
They thrive in permanent bodies of water and are often seen basking along the shoreline. Opportunistic feeders, bullfrogs eat nearly anything they can overpower — including insects, fish, smaller frogs, and even small birds or snakes. Their appetite and adaptability have allowed them to spread widely, sometimes outcompeting native species.
In Illinois, bullfrogs are common statewide and are often the first frog beginners encounter. However, their success comes with ecological challenges. Because they can dominate habitats and prey on native species, bullfrogs are sometimes considered an invasive problem outside their native range. Still, within Illinois, they’re an iconic sound of summer nights and an essential part of wetland ecosystems.
2. Green Frog (Lithobates clamitans)
Slightly smaller and leaner than the Bullfrog, the Green Frog is another familiar resident of Illinois waterways. Growing 3–4 inches long, this frog is known for its bright green face and the distinct dorsolateral ridges running from the eyes down the back — a key feature that separates it from the Bullfrog.
Its call is a short, banjo-like “gunk!” — as if someone plucked a loose rubber band. Males typically call from the edges of ponds or lakes during summer evenings, often while half-submerged. Green Frogs prefer permanent water sources but are also found in ditches, streams, and backyard ponds.
Coloration varies from green to bronze or brown, sometimes with darker mottling. Their bellies are white to pale yellow. The tympanum (eardrum) is prominent, with males again showing a yellow throat during mating season. Tadpoles overwinter and metamorphose in the following year, making them visible year-round.
In Illinois, Green Frogs are widespread and a reliable sign of healthy wetlands. They help control mosquito populations and serve as prey for fish, birds, and mammals. Observers often mistake them for Bullfrogs, but the presence of ridges and their smaller size are giveaways. They’re a wonderful species for new frog-watchers to learn identification skills.
3. Northern Leopard Frog (Lithobates pipiens)
The Northern Leopard Frog is a striking amphibian and one of Illinois’s most easily recognized species. Its body is covered in dark, rounded spots outlined by lighter borders, resembling the pattern of a leopard’s coat — hence the name. Adults typically measure 2–4 inches and display shades of green or brown.
Found throughout northern and central Illinois, Leopard Frogs inhabit meadows, wetlands, and grasslands near permanent water. They are strong jumpers and often seen far from the water during summer rains, moving across fields or roads in search of food or breeding sites.
Their call is a distinctive snore-like croak that can carry long distances in early spring. Breeding occurs in temporary pools, where females lay up to several thousand eggs. The tadpoles metamorphose by midsummer, growing rapidly in warm, shallow waters.
Leopard Frogs play an important ecological role, feeding on insects, spiders, and small invertebrates. However, populations have declined in parts of the Midwest due to habitat loss, pesticide exposure, and disease. Conservation efforts focus on protecting clean wetlands and maintaining corridors that connect breeding habitats.
Watching a Northern Leopard Frog leap through Illinois grasslands is a reminder of how dynamic and colorful the state’s amphibian life can be.
4. Plains Leopard Frog (Lithobates blairi)
Closely related to the Northern Leopard Frog, the Plains Leopard Frog is more common in the western and southern parts of Illinois. At first glance, they look similar, but one key difference helps identify them: the dorsolateral fold breaks near the base of the body and turns inward — a small detail that frog enthusiasts quickly learn to spot.
These frogs are generally tan to olive-brown with dark, irregular spots. They grow between 2 and 4 inches and favor open, grassy wetlands, roadside ditches, and temporary ponds. Their call is a rapid, chuckling snore, often heard at night during spring rains.
Plains Leopard Frogs are highly adaptable and tolerate moderate disturbance, which allows them to survive in agricultural areas and suburban landscapes. They feed primarily on insects but are known to eat small aquatic organisms as well.
Because their breeding pools often dry up, timing is critical — they mate quickly after spring rains and their tadpoles must develop fast before water levels drop. Their survival showcases nature’s resilience in ever-changing Illinois weather patterns.
Although less common than Northern Leopard Frogs, the Plains species adds diversity to the state’s amphibian population and reflects the transition from northern wetlands to the Great Plains.
5. Southern Leopard Frog (Lithobates sphenocephalus)
The Southern Leopard Frog is another spotted beauty that completes the trio of leopard species in Illinois. Found mainly in southern counties, this frog prefers warmer climates and more stable water bodies such as ponds, swamps, and slow-moving streams.
They can reach 3–4 inches long and display bright green to brown coloring with dark oval spots. The snout is more pointed than that of the Northern Leopard Frog, and they often have a light line along the upper jaw. Unlike some northern species, Southern Leopard Frogs are active for longer seasons due to the milder climate.
Their call sounds like a rapid series of chuckles or clucks, often overlapping in large choruses during breeding season, typically from February to May. Females deposit large egg masses that hatch within a few days, with tadpoles maturing by midsummer.
These frogs are vital insect controllers and form a key part of southern Illinois wetland food chains. They’re agile, quick to leap, and often one of the first species to call after warm spring rains. Observing their activity at night — illuminated by a flashlight beam — offers one of the most delightful sights for frog enthusiasts exploring the state’s southern wetlands.
6. Pickerel Frog (Lithobates palustris)
The Pickerel Frog is one of the most elegant frogs you’ll find in Illinois, easily identified by its neat rows of chocolate-brown, square-shaped spots that line up like checkers along its back. Its orderly patterning and golden-bronze coloration make it stand out among the state’s amphibians. Adults measure between 2 and 4 inches long and are often mistaken for the more randomly spotted Leopard Frog—but once you’ve seen the Pickerel’s clean lines, the difference is clear.
This species prefers cool, clean, spring-fed waters, such as small streams, clear ponds, and shaded wetlands. Because it requires high water quality, the Pickerel Frog is often considered an indicator species—its presence signals a healthy ecosystem. When disturbed, it leaps gracefully into the water and can stay submerged for long periods thanks to its excellent oxygen absorption through the skin.
One fascinating fact about Pickerel Frogs is that their skin secretes mild toxins that can irritate predators (and even human skin if handled excessively). These secretions help protect them from snakes and mammals that might otherwise make a meal of them. While not dangerous to humans, it’s best to admire these frogs without touching.
Pickerel Frogs breed in early spring, laying clusters of eggs in shallow water. Their call is a low, steady snore—shorter and quieter than that of the Leopard Frog. During the summer, they can be found along grassy banks or in shaded areas close to the water’s edge, preying on insects, worms, and small crustaceans.
In Illinois, populations remain relatively stable but localized. Protecting clean streams and avoiding pollution runoff is essential for keeping these tidy-patterned amphibians thriving across the state.
7. Crawfish Frog (Lithobates areolatus)
If you hear a deep, resonant snore coming from a prairie field at night, you might be listening to a Crawfish Frog. Named for its unusual habit of living in abandoned crayfish burrows, this burrow-dwelling frog is one of Illinois’s most secretive species. Adults range from 3 to 5 inches long and have large dark spots bordered with light halos—somewhat like the Leopard Frogs but fewer in number and larger in size.
Crawfish Frogs inhabit open grasslands, floodplains, and wet meadows. Because they rely on crayfish burrows for shelter and moisture, they are rarely seen above ground except during rainy spring nights when they migrate to temporary pools to breed. Their call—a loud, hollow snore that can carry hundreds of yards—is one of the earliest frog sounds of the season.
This species is considered rare in Illinois and is listed as a species of concern due to habitat loss. The draining of prairies and wetlands has drastically reduced their available homes. However, conservation programs that restore native grasslands and wet prairies have begun to improve their outlook.
Ecologically, Crawfish Frogs play a unique role by aerating soil through their burrowing activity and providing a link between aquatic and terrestrial food webs. They feed mainly on insects, spiders, and small crustaceans that wander near their burrow entrances. Observing one in the wild is a special treat—these frogs represent the vanishing grassland heritage of Illinois.
8. Wood Frog (Lithobates sylvaticus)
Among the most extraordinary types of frogs in Illinois, the Wood Frog stands out for one remarkable ability—it can survive being frozen solid during winter. Found primarily in northern Illinois, these small brown frogs are forest dwellers, living under leaf litter and near woodland ponds. They typically grow 1.5–3 inches long and can be recognized by a distinct dark “mask” that runs across the eyes, giving them a bandit-like appearance.
In early spring—sometimes when snow still lingers—Wood Frogs emerge to breed in vernal pools. Males call with a soft quacking sound, forming huge choruses that fill forest clearings. After laying eggs, adults retreat back into the woods, where they remain hidden for most of the year.
Their freezing ability is one of nature’s marvels. As temperatures drop, Wood Frogs allow ice to form around their organs while glucose acts as a natural antifreeze, preventing cell damage. When warmth returns, they thaw and resume normal activity—a process that seems almost miraculous.
Wood Frogs play a crucial ecological role by providing early food for snakes, birds, and small mammals emerging from hibernation. Unfortunately, habitat fragmentation threatens their breeding pools, which must hold water only seasonally to prevent fish predation on eggs. Protecting forest wetlands is essential to their survival.
Spotting a Wood Frog on a chilly March day in northern Illinois is a reward for those who venture outdoors early—proof that even in frozen landscapes, life endures.
9. Eastern Gray Treefrog (Dryophytes versicolor)
Perched high in trees or clinging to window screens on humid nights, the Eastern Gray Treefrog is one of Illinois’s most charming amphibians. Despite its name, it’s not always gray—its color shifts between gray and bright green depending on surroundings and temperature. Adults measure about 1.5 to 2 inches long and can be identified by the bright orange or yellow patches on their inner thighs, visible when they leap.
These frogs are masters of camouflage, blending perfectly with bark, leaves, and even siding. They inhabit wooded areas, backyards, and suburban gardens, especially where trees overhang ponds or pools. Their musical trill, a soft, bird-like call, fills summer nights across much of Illinois.
Eastern Gray Treefrogs spend most of their lives in trees, coming down mainly to breed in temporary ponds or rain-filled ditches. They lay small clusters of eggs attached to vegetation, and tadpoles develop quickly in warm summer water. As insectivores, they play an important role in controlling mosquitoes, moths, and other nocturnal insects.
Interestingly, these frogs have the ability to withstand freezing temperatures like the Wood Frog, entering a dormant state during winter under bark or leaf litter. Their resilience and adaptability make them one of the most successful treefrog species in the Midwest.
Although common, their populations depend on tree cover and clean breeding sites. Encouraging native vegetation and minimizing pesticide use can help ensure their cheerful trills continue to echo through Illinois summer nights.
10. Cope’s Gray Treefrog (Dryophytes chrysoscelis)
Nearly identical in appearance to its cousin, the Eastern Gray Treefrog, Cope’s Gray Treefrog can be distinguished only by its faster, higher-pitched call. Both species share the same range in Illinois, often inhabiting the same wooded areas, which makes auditory identification essential for naturalists.
Adults are small, usually 1.25–2 inches long, with mottled gray, green, or brown skin and the same telltale orange thigh patches. Like their relatives, they can change color for camouflage and are mostly nocturnal, perching on leaves, tree trunks, or windows near lights where insects gather.
Cope’s Gray Treefrogs prefer slightly warmer, more open habitats—wooded edges, floodplain forests, and suburban yards. Their call resembles a fast, buzzing trill lasting one to two seconds, most often heard on warm, humid nights in late spring.
These frogs breed in temporary pools or even large puddles, and the males form loud choruses that can be heard far beyond the water’s edge. Tadpoles mature in a few weeks, feeding on algae and detritus before metamorphosing into tiny, tree-climbing juveniles.
Ecologically, they are highly beneficial for insect control and are often welcomed by homeowners with natural ponds. Despite urban development, they remain common due to their adaptability and small habitat needs. Seeing one clinging to a window or porch light is a charming reminder that wild nature still thrives in Illinois neighborhoods.
11. Blanchard’s Cricket Frog (Acris blanchardi)
Small, fast, and full of energy, the Blanchard’s Cricket Frog is one of the tiniest and most active frog species in Illinois. Measuring just 0.75 to 1.5 inches long, this miniature amphibian might be small, but it makes a big impression with its constant hopping along pond edges and its sharp, clicking call that resembles the sound of two pebbles tapped together.
Unlike many frogs, Cricket Frogs are more terrestrial and diurnal—they’re often seen during the day darting along muddy banks or basking on rocks. Their coloration varies widely, from grayish-brown to green or reddish tones, often with a dark triangle between the eyes and a faint dorsal stripe. This camouflage helps them blend into their surroundings, whether it’s a gravel path or a patch of aquatic vegetation.
Blanchard’s Cricket Frog inhabits ponds, marshes, and slow-moving streams across Illinois, particularly in the southern and central regions. Their populations are sensitive to changes in water quality, which has led to local declines in some areas due to pollution, agricultural runoff, and habitat loss.
These tiny frogs feed on small insects like gnats, ants, and mosquitoes, helping to control pest populations. They are also prey for fish, snakes, and birds, forming a vital link in the food web. Their high activity level and quick reflexes make them difficult to capture—even experienced herpetologists struggle to keep up with their zigzagging leaps!
Conservation efforts focus on maintaining clean, shallow wetlands and preventing excessive pesticide use. Despite their size, Blanchard’s Cricket Frogs play an outsized role in Illinois ecosystems—and hearing their cheerful “click-click-click” chorus is a sure sign that summer has arrived.
12. Spring Peeper (Pseudacris crucifer)
Every year, as winter loosens its grip and the first warm rains fall, the Spring Peeper announces the change of seasons in Illinois. This tiny chorus frog—barely an inch long—produces one of the loudest and most recognizable calls in the state: a clear, high-pitched “peep-peep-peep” that can carry for hundreds of feet on cool spring nights.
Spring Peepers are easy to identify by the dark “X”-shaped mark across their back, from which their scientific name crucifer (“cross-bearer”) is derived. Their skin ranges from tan to light brown, and they often appear almost translucent under flashlight beams. These frogs spend most of their lives hidden in leaf litter, emerging in late March or April to breed in temporary woodland pools.
Their mating calls create a breathtaking nighttime chorus, with thousands of males calling simultaneously in the wetlands. After breeding, adults retreat back into the forest, where they feed on small insects and other invertebrates throughout summer.
Despite their small size, Spring Peepers are hardy creatures capable of surviving freezing temperatures by producing natural antifreeze compounds in their blood. They’re most abundant in wooded areas and forested wetlands in central and southern Illinois.
For many nature lovers, the sound of Spring Peepers is a beloved symbol of renewal—the first sign that spring has truly arrived. Their presence not only brings joy to listeners but also signals healthy seasonal wetlands that support countless other species.
13. Western Chorus Frog (Pseudacris triseriata)
If you’ve ever heard a sound that resembles someone running a fingernail along a comb during early spring evenings, you’ve likely encountered the Western Chorus Frog. This small but vocal species is one of the first to call in Illinois each year, often beginning its chorus while snow still lingers on the ground.
Western Chorus Frogs are slender, about 1 to 1.5 inches long, and have three dark stripes running down their light tan or gray backs. They’re found throughout Illinois but are most common in northern and central regions, inhabiting shallow wetlands, roadside ditches, and flooded fields.
During breeding season (March to May), males gather in large groups in temporary pools, producing their rasping calls to attract females. Egg clusters are attached to vegetation, and tadpoles develop quickly before the pools dry up in early summer.
Outside of breeding, these frogs are rarely seen—they spend most of their time under logs or leaf litter, hunting small insects and avoiding predators. Their cryptic coloration provides excellent camouflage, making them nearly invisible against the forest floor.
The Western Chorus Frog is an ecological indicator species; its presence signals healthy, seasonal wetlands essential to many amphibians. Urbanization and drainage of temporary ponds have reduced their habitats in some regions, but they remain one of the most widespread types of frogs in Illinois.
When their calls echo through the night, it’s a sure sign that the prairie wetlands are waking up again after winter’s rest.
14. Boreal Chorus Frog (Pseudacris maculata)
The Boreal Chorus Frog looks and sounds much like its western cousin but inhabits more northern climates and slightly cooler environments. In Illinois, it’s typically found in the far northern counties, thriving in cool, grassy wetlands, marshes, and floodplains.
Adults are small—usually around 1 inch long—with light brown to olive coloration and three dark dorsal stripes that may break into spots. Their call is similar to the Western Chorus Frog’s “comb-like” trill but is slightly longer and more musical. Breeding occurs early in spring, often right after snowmelt, when males gather in temporary ponds to sing through cold nights.
Boreal Chorus Frogs are adapted to shorter summers, so their tadpoles develop quickly to ensure they transform into froglets before seasonal ponds dry up. Adults spend the rest of the year hidden under vegetation or burrowed into moist soil.
Because they are cold-tolerant and breed in isolated habitats, Boreal Chorus Frogs are less affected by predators but more sensitive to habitat destruction and pollution. They are among the first amphibians to emerge in spring, making them a key part of early-season wetland ecosystems.
Their quiet resilience and delicate trills remind us how amphibians persist in even the harshest Midwest climates. For wildlife watchers, hearing a Boreal Chorus Frog at dusk is a fleeting but magical experience—one that marks the arrival of life after winter
15. American Green Treefrog (Dryophytes cinereus)
Bringing a splash of vibrant color to the wetlands, the American Green Treefrog is one of the most visually striking types of frogs in Illinois. Its smooth, bright green body, highlighted by a clean white or yellow stripe running along each side, makes it easy to recognize. Adults grow 1.25–2.5 inches long and are slender, agile climbers with sticky toe pads that help them cling to reeds and leaves.
Though more common in the southeastern United States, this species reaches its northernmost range in southern Illinois, where it inhabits cypress swamps, floodplain forests, and lakesides with abundant vegetation. On humid summer nights, its loud, bell-like “quonk-quonk-quonk” call can echo from the reeds, sometimes blending into a chorus with other treefrogs.
Green Treefrogs are highly adapted to life among the leaves—they spend most of their time above water, hunting flies, mosquitoes, and small moths. Their coloration can shift slightly to match surroundings, offering camouflage from predators like birds and snakes.
Breeding occurs from late spring through midsummer. Females attach egg clusters to submerged plants, and tadpoles metamorphose within weeks. These frogs are excellent indicators of wetland health and are popular among wildlife enthusiasts for their cheerful presence and photogenic looks.
While limited in range, the American Green Treefrog’s growing population in southern Illinois shows how climate and habitat connectivity are allowing some southern species to expand northward—a hopeful sign of adaptability amid environmental change.
16. Bird-voiced Treefrog (Dryophytes avivoca)
The Bird-voiced Treefrog is one of Illinois’s most enchanting and elusive amphibians. As its name suggests, its call resembles the song of a bird more than a frog—a soft, melodic “wit-wit-wit” that echoes through southern Illinois swamps on warm summer nights. This treefrog is a true hidden gem for wildlife enthusiasts who venture into the state’s cypress-tupelo wetlands.
Bird-voiced Treefrogs are small, measuring around 1.5–2 inches in length, with a mottled gray or green body that helps them blend perfectly with tree bark. Like other treefrogs, they possess sticky toe pads that allow them to climb effortlessly on smooth leaves and branches. Their inner thighs feature subtle green or yellow patches—less vivid than the orange of Gray Treefrogs but still a helpful identification clue.
They prefer swampy floodplain forests and cypress ponds, especially in southern Illinois near the Cache River Basin and Shawnee National Forest. Because they spend most of their lives high in trees, they are rarely seen except during breeding season. Males call from low shrubs or vegetation overhanging water, often after heavy rains in May or June.
These frogs are nocturnal insectivores, feeding primarily on mosquitoes, beetles, and moths. Their presence is a good indicator of healthy wetland forests with clean water and mature tree cover. Unfortunately, habitat loss and alteration of natural flood patterns have limited their range in Illinois.
Spotting—or even hearing—a Bird-voiced Treefrog in the wild is a rare privilege. For many naturalists, this species represents the quieter, subtler beauty of the state’s southern wetlands, where ancient trees meet the timeless rhythm of amphibian song.
17. Illinois Chorus Frog (Pseudacris illinoensis)
Few frogs are as geographically unique as the Illinois Chorus Frog—a species found only in a small portion of the Midwest, with its core range centered in southern and central Illinois. This small, sandy-colored frog is an Illinois native specialty, known for its burrowing lifestyle and its distinctive, squeaky call that sounds almost like someone rubbing a balloon.
Adults reach about 1–1.5 inches in length, with smooth, pale gray or tan skin marked by faint darker blotches. Their most remarkable adaptation is a set of spade-like tubercles on their hind feet, which allow them to dig quickly into loose sandy soil. Unlike most frogs, the Illinois Chorus Frog spends most of its life underground, emerging only briefly in early spring to breed.
Breeding occurs in shallow, temporary pools that form after late-winter or early-spring rains. Males call from the water’s edge, producing high-pitched, nasal “eeek-eeek” notes that can carry surprisingly far on quiet nights. After breeding, adults return underground, where they remain hidden for much of the year.
Because they depend on sandy soils and ephemeral wetlands, Illinois Chorus Frogs are extremely sensitive to habitat disturbance. Agricultural development, road construction, and drainage of wetlands have greatly reduced their range. They are currently listed as a threatened species in Illinois.
Their story serves as a reminder of how delicate amphibian habitats can be. Protecting their sandy prairies and floodplain pools is vital to preserving this little-known, yet distinctly local, type of frog in Illinois.
18. Plains Spadefoot Toad (Spea bombifrons)
Though technically a toad, the Plains Spadefoot is often included among Illinois’s frog species due to its amphibious lifestyle and similar biology. It’s one of the most fascinating types of frogs in Illinois thanks to its incredible adaptability to dry environments.
Named for the dark, keratinized “spade” on each hind foot used for digging, the Plains Spadefoot spends most of its life buried underground in dry prairie soils. Adults are 1.5–2.5 inches long, with a rounded body, large eyes featuring vertical pupils, and grayish-brown skin marked by subtle darker patches. Despite their modest looks, these amphibians are remarkable survivors.
When heavy rains arrive—sometimes after months of drought—Plains Spadefoots emerge en masse to breed in temporary pools. Their call is a loud, duck-like snore that can be heard across open grasslands. They breed quickly, laying eggs that hatch within a day, and tadpoles metamorphose in as little as two weeks, beating the clock before the puddles dry up again.
In Illinois, they’re primarily found in the western and southwestern prairies, particularly in sandy or loamy soils. During dry periods, they burrow deep into the ground, entering a state of torpor to conserve moisture and energy.
Despite their rarity, Spadefoots are critical for prairie ecosystems—they consume insects like beetles and crickets and serve as prey for snakes and birds. Their ability to endure extreme conditions makes them a symbol of resilience in Illinois’s ever-changing landscape.
19. Eastern Narrow-mouthed Toad (Gastrophryne carolinensis)
The Eastern Narrow-mouthed Toad might look a little odd at first glance—but this small, secretive amphibian is one of the most intriguing members of Illinois’s frog family. Despite its name, it’s not a true toad but a distinct species with smooth, moist skin and a squat, wedge-shaped body.
Adults average about 1 to 1.5 inches long and have a sharply pointed snout with a tiny mouth—hence the name. Their coloration ranges from gray to brown or reddish, often with darker mottling. They are most common in southern Illinois, inhabiting moist forests, floodplains, and grassy areas near wetlands.
Narrow-mouthed Toads are burrowers, spending much of their lives hidden under logs, leaf litter, or soil. They emerge after warm rains to feed, primarily on ants and termites, using their sticky tongues to capture prey. To avoid ant bites, they produce a special skin secretion that repels insects—a clever evolutionary defense!
Their call is a long, nasal “weeeeee” sound, often compared to the bleat of a distant sheep. Breeding occurs during summer rainstorms in shallow temporary pools. Females lay eggs that hatch within days, and tadpoles metamorphose rapidly before water levels drop.
Though seldom seen, these frogs are more common than people realize—they’re just experts at staying hidden. Their unique adaptations and specialized diet make them an important ecological niche-filler in Illinois’s amphibian communities.
20. Western Toad (Anaxyrus boreas)
Rounding out our list of the 20 Types of Frogs in Illinois is the Western Toad, a hardy amphibian known for its warty skin and gentle temperament. Although it’s more common in the western United States, small populations have been recorded in western Illinois near river floodplains and transitional grasslands.
Western Toads are large, reaching 3–5 inches in length. They have dry, bumpy skin with a white dorsal stripe running from head to lower back. Their coloration ranges from olive to tan, sometimes with darker blotches. Unlike many frogs, they don’t have a loud mating call—males produce only a quiet chirp or squeak when touched, which adds to their mysterious reputation.
These toads prefer open habitats—prairies, riverbanks, and woodland edges—where they burrow during the day and emerge at night to feed on insects, worms, and spiders. Their diet helps control pests naturally, making them beneficial allies to the ecosystem.
Breeding occurs in late spring in shallow ponds or slow-moving streams. Females lay long, gelatinous strings of eggs that wrap around aquatic vegetation. Tadpoles form large schools that can darken the water’s surface before metamorphosing into small toadlets by midsummer.
Though not common, the Western Toad symbolizes the rugged adaptability of amphibians in the Midwest. Its ability to survive in variable conditions, combined with its gentle disposition, makes it a fitting conclusion to our exploration of Illinois’s remarkable frogs and toads.
FAQ’s
1. How many species of frogs are in Illinois?
Illinois is home to around 20 native species of frogs and toads. This includes common species like the American Bullfrog, Green Frog, and Spring Peeper, as well as rare ones such as the Bird-voiced Treefrog and Illinois Chorus Frog. Each species has its own habitat preference, making Illinois one of the most amphibian-rich states in the Midwest.
2. Where to find frogs in Illinois?
You can find frogs anywhere there’s fresh water in Illinois — ponds, wetlands, streams, and floodplain forests. Popular places include the Cache River Wetlands, Shawnee National Forest, and Starved Rock State Park. Even suburban ponds or backyard gardens with clean water often attract frogs.
3. What is the largest frog in Illinois?
The American Bullfrog is the largest frog in Illinois and North America. Adults can reach up to 8 inches long and weigh over a pound. Their deep “jug-o-rum” call can be heard around lakes and ponds throughout the summer months.
4. What kinds of frogs are there?
Illinois has several types of frogs: true frogs like Bullfrogs and Green Frogs, treefrogs such as Gray Treefrogs and Spring Peepers, chorus frogs that sing in early spring, and toads, which have drier skin and spend more time on land. Each plays a unique role in the state’s ecosystems.
5. Are there any poisonous frogs in Illinois?
No, Illinois does not have any deadly poisonous frogs. Some toads secrete mild toxins from their skin to discourage predators, but they aren’t harmful to humans unless ingested. Always wash your hands after handling any frog or toad to protect both you and the animal.
6. Is there a frog season in Illinois?
Yes. Frog activity peaks from March to September. Spring brings the loudest mating calls, especially after warm rains. By late fall, frogs prepare for winter hibernation as temperatures begin to drop.
7. What is the difference between a frog and a toad in Illinois?
Frogs have smooth, moist skin and stay close to water, while toads have rough, dry, warty skin and live mostly on land. Frogs lay eggs in clusters; toads lay them in long strings. Both are amphibians and share similar life cycles.
8. Where do frogs go in the winter in Illinois?
Frogs in Illinois hibernate when winter arrives. Aquatic frogs rest at the bottom of ponds, absorbing oxygen through their skin. Land-dwelling frogs and toads dig into soil or leaf litter to stay warm until spring returns.
9. What is the Vietnamese giant tree frog?
The Vietnamese Giant Tree Frog, native to Southeast Asia, is known for its large size and bright green color. It’s not found in Illinois but sometimes appears in the exotic pet trade. It’s best admired in the wild where it naturally thrives.
10. Are toads in Illinois poisonous to dogs?
Toads in Illinois, like the American Toad, produce mild toxins called bufotoxins. These can cause drooling or mild irritation if a dog licks a toad but are rarely dangerous. If this happens, rinse your dog’s mouth gently and contact your vet for advice.
11. What’s the difference between frogs and toads?
All toads are frogs, but not all frogs are toads. Frogs have smoother skin and longer legs, perfect for swimming and jumping, while toads have dry, bumpy skin and shorter legs. Frogs prefer water; toads do better on land.
12. Is it illegal to catch frogs in Illinois?
You can catch frogs in Illinois if you have a valid fishing license and follow state regulations. The Illinois Department of Natural Resources allows seasonal frog hunting, mainly from mid-June to early October. Always check the latest IDNR rules before collecting frogs.
13. How can I tell if a frog is poisonous?
Bright, vibrant colors often signal danger, but Illinois frogs are generally dull green, gray, or brown, meaning they’re harmless. True poisonous frogs live mostly in tropical regions like Central and South America.
14. How to keep frogs out of your yard?
Reduce standing water where frogs breed, such as puddles or buckets. Trim tall grass, and install motion lights to deter insects — their main food source. Still, remember that frogs help control pests, so it’s best to leave them alone when possible.
15. Where do frogs live in Illinois?
Frogs live in ponds, wetlands, forests, and even backyards across Illinois. Some prefer trees, like Gray Treefrogs, while others, such as Bullfrogs, stick to larger lakes and slow-moving rivers.
16. What month do frogs come out?
Frogs usually emerge in March or April when nights stay above freezing. Early callers like the Western Chorus Frog can be heard even when ice is still melting. By late spring, most species are active and breeding.
17. Is it safe to keep a frog as a pet?
Yes, if done responsibly. Pet-friendly species like White’s Treefrogs or Pacman Frogs adapt well in captivity. However, wild Illinois frogs should never be taken home — they’re protected and don’t survive well outside their natural environment. Always buy from a licensed breeder.
Conclusion
From the frozen forests of northern Illinois to the warm swamps of the south, the state’s frogs display incredible diversity and resilience. Each species—large or small, loud or quiet—plays an essential role in maintaining the balance of local ecosystems. Learning to recognize these frogs helps us appreciate the delicate connections between land, water, and wildlife.
Whether you’re standing by a pond on a humid summer night or hiking through an early spring woodland, listen closely. The chorus of Illinois frogs is more than background music—it’s a living symphony of nature, echoing the health and wonder of the world around us.
Read more: