21 Types of Frogs in Maryland: A Guide to Every Native Species You’ll Encounter
October 21, 2026
Maryland’s tidal marshes, Piedmont streams, and Appalachian forests pack an outsized amount of amphibian diversity into one mid-Atlantic state. Anyone researching the types of frogs in Maryland quickly finds a lineup that ranges from a four-inch predator with a bass “jug-o-rum” call to a half-inch chorus frog that can out-sing a car alarm. Identifying Maryland frog species isn’t just a backyard curiosity, either, since several are used as indicators of wetland health across the Chesapeake Bay watershed.
This guide walks through every native and established species recorded in the state, organized by family, with the physical markers, calls, and habitats that separate one from another. Whether the goal is frog identification in Maryland for a nature journal or simply figuring out what’s singing in the backyard pond, the details below cover all 21 species on the state’s official list.
1. American Toad
The American Toad (Anaxyrus americanus) is one of only two true toads living in Maryland, and it’s usually the first one most residents meet. Maryland’s Department of Natural Resources notes that the American toad and Fowler’s toad can be distinguished from each other based on the number of warts in each pigmented spot on the dorsum, the presence or absence of conspicuously enlarged warts on the tibia, and spotting on the chest. This toad favors gardens, woodland edges, and backyard leaf piles, where its warty, dry skin and short hopping legs set it apart from the smooth-skinned, long-legged frogs covered later in this guide.
Pro Tip: Toads have dry, bumpy skin and waddle more than they leap, while true frogs have smooth or slightly textured skin and powerful jumping legs. Checking skin texture first narrows down identification fast.
2. Fowler’s Toad
Maryland’s second true toad, the Fowler’s Toad (Anaxyrus fowleri), overlaps heavily with the American toad in range but tends to favor sandier soils near the coastal plain and riverbanks. The state’s field guide documents photographed individuals from Glen Burnie, confirming the species’ presence across the Baltimore region. Because the two toads look so similar at a glance, wart count and chest pattern remain the most reliable field marks.
| Feature | American Toad | Fowler’s Toad |
|---|---|---|
| Warts per dark spot | One or two large warts | Three or more smaller warts |
| Chest pattern | Usually unspotted | Often spotted |
| Preferred soil | Loamy, garden-friendly | Sandy, coastal plain |
3. Eastern Narrow-Mouthed Toad
Despite the name, the Eastern Narrow-mouthed Toad (Gastrophryne carolinensis) isn’t a true toad at all, it’s the sole Maryland representative of family Microhylidae. The species carries state Endangered status, and its mottled brown, red, or gray skin, pointed snout, and small size make it easy to overlook in leaf litter. It also preys heavily on ants and small invertebrates, a role shared by several other soil-dwelling species covered in this guide on types of beetles in Maryland, which it often shares habitat with.
4. Eastern Spadefoot
The Eastern Spadefoot (Scaphiopus holbrookii) is Maryland’s only spadefoot toad, representing an entire family (Pelobatidae) on its own in the state. Spadefoots spend most of the year burrowed underground using the hardened “spade” on each hind foot, emerging in large numbers only after heavy summer rains to breed explosively in temporary pools. Related spadefoot species occupy similar desert and grassland burrows farther west, including the species covered in this roundup of types of frogs in Arizona.
5. American Bullfrog
The American Bullfrog (Lithobates catesbeianus) is the largest frog in Maryland and arguably the most recognizable. According to Maryland DNR’s field guide, adult bullfrogs run 3½ to 6 inches with a record of 8 inches, appearing plain green above with no dorsolateral ridges, and the species is best located by listening for its distinctive bass “jug-o-rum” call from late April through July. The Chesapeake Bay Program reports that the American bullfrog can grow up to 16 inches with its legs fully extended and weigh up to a pound, making it a formidable hunter of nearly anything smaller than itself.
Key Insight: Bullfrogs are native to Maryland but become a problem elsewhere. Populations introduced to ponds in California and even Hawaii have outcompeted native amphibians, a pattern wildlife agencies now actively manage.
6. Green Frog
The Green Frog (Lithobates clamitans) is frequently mistaken for a young bullfrog, since both are green or bronze and live near almost any pond, lake, or slow stream in the state. The giveaway is the dorsolateral ridge, two raised folds of skin running down the back, which extends the full length of the body on a green frog but is absent on a bullfrog. Males of both species develop bright yellow throats once they reach breeding maturity.
Common Mistake: Assuming any plain-green frog near water is a bullfrog. Always check for the dorsolateral ridge before sizing it as either species.
| Feature | American Bullfrog | Green Frog |
|---|---|---|
| Dorsolateral ridge | Absent | Present, full length |
| Typical size | 3.5–6 inches | 2–3.5 inches |
| Call | Low “jug-o-rum” | Single banjo-like “gunk” |
7. Carpenter Frog
The Carpenter Frog (Lithobates virgatipes) holds Watchlist status in Maryland, meaning wildlife managers track it closely even though it isn’t yet listed as threatened. It appears on the state’s official amphibian checklist with that Watchlist designation. Named for a call that sounds like two carpenters hammering nails in alternating rhythm, this species sticks to acidic bogs, cranberry fens, and coastal plain wetlands. Its range extends down the Atlantic coastal plain into territory covered by this guide to types of frogs in North Carolina.
8. Pickerel Frog
The Pickerel Frog (Lithobates palustris) is one of the most common true frogs statewide and the only one in Maryland with a genuine chemical defense. The Maryland State Archives describes its distinct pattern of square-shaped dorsal spots, and notes that to dissuade predators, it secretes a toxic oil that acts as a mild irritant to humans. That skin secretion is mild compared to the far more potent chemical defenses found in this overview of poisonous frog species worldwide, but it’s still enough to deter most predators and to make handling this frog a wash-your-hands-afterward affair.
9. Northern Leopard Frog
Unlike every other species on this list, the Northern Leopard Frog (Lithobates pipiens) is not native to Maryland. Maryland’s official checklist marks it as an introduced species, and the Maryland State Archives adds that it is typically green or light brown with distinct dark spots, light dorsal ridges, and noticeable light-colored stripes running from nose-tip to shoulder, reaching 2 to 3.5 inches in length. In Maryland it turns up mostly in the western counties, a pattern that mirrors its historically abundant status farther north and west.
10. Southern Leopard Frog
The Southern Leopard Frog (Lithobates sphenocephalus) replaces its northern cousin across most of the coastal plain and takes over as the default leopard frog in lower Maryland. It shows a green or brown body peppered with dark spots on the back, sides, and front legs, and a small white spot sits at the center of the eardrum, a detail that separates it at a glance from the Mid-Atlantic Coast Leopard Frog discussed next.
11. Mid-Atlantic Coast Leopard Frog
The Mid-Atlantic Coast Leopard Frog (Lithobates kauffeldi) is the newest addition to Maryland’s amphibian list, and it’s barely a decade old as a recognized species. Maryland’s herpetological checklist lists it as a new species described by Feinberg and colleagues in 2014, and it currently appears on the state’s confirmed inventory via the Maryland Biodiversity Project. It occupies a narrow range in the northeast corner of the state, overlapping the southern and northern leopard frogs just enough to make call identification the only reliable way to separate all three.
| Species | Maryland Range | Status |
|---|---|---|
| Northern Leopard Frog | Western counties | Introduced |
| Southern Leopard Frog | Coastal plain, statewide south | Native |
| Mid-Atlantic Coast Leopard Frog | Northeast corner | Native, recently described |
12. Wood Frog
The Wood Frog (Lithobates sylvaticus) is famous for breeding earlier than almost any other Maryland amphibian, sometimes calling while ice still lines the edges of vernal pools. The Maryland DNR’s native animal profile notes that reports of early spring frog calls each year usually come from either the wood frog or the spring peeper. Its tan, brown, or gray body with a dark mask-like marking across the face makes it easy to pick out once found, even though its camouflage works well against forest leaf litter. Its range also stretches north into territory shared with this guide’s companion piece on types of frogs in Pennsylvania.
Pro Tip: Late February through March, during the first warm rain after a cold spell, is prime time to hear both wood frogs and spring peepers calling together at vernal pools.
13. Barking Treefrog
The Barking Treefrog (Hyla gratiosa) carries state Endangered status and represents the rarest treefrog on Maryland’s list. It’s also the largest native treefrog in the state, with a plump body and a call that genuinely resembles a dog’s bark delivered from high in the canopy or while floating on open water. Its range barely creeps into Maryland from the south, overlapping territory covered in this look at types of frogs in South Carolina, where the species is considerably more common.
14. Gray Treefrog
The Gray Treefrog (Hyla versicolor) earns its scientific name from a genuine color-changing ability, shifting between gray, green, and brown depending on temperature, humidity, and background. Its mottled, lichen-like back pattern provides excellent camouflage against tree bark, and bright yellow patches hidden on the inner thighs flash briefly when it jumps. This species is essentially identical in appearance to the next one on this list and can only be told apart with certainty by call or chromosome count.
15. Cope’s Gray Treefrog
Visually, Cope’s Gray Treefrog (Hyla chrysoscelis) is a near-perfect twin of the standard gray treefrog, down to the same color-shifting skin and hidden thigh patches. The reliable difference is the call: Cope’s gray treefrog trills noticeably faster and higher-pitched than its look-alike cousin. The two species also differ genetically, with Cope’s gray treefrog carrying half the chromosome number of the regular gray treefrog, though that distinction obviously isn’t useful in the field.
16. Green Treefrog
The Green Treefrog (Hyla cinerea) is a bright, smooth-skinned species usually sporting a clean lime-green back with a pale cream or white stripe running down each side. It favors marshes, lake edges, and vegetation overhanging permanent water, and its range in Maryland sits near the northern edge of where the species is common along the Atlantic coast. Populations of the same species have also become established well outside their native range, including introduced groups discussed in this guide to different types of frogs found across the country.
| Treefrog | Typical Color | Standout Trait |
|---|---|---|
| Barking Treefrog | Green to brown, spotted | Dog-like bark call |
| Gray Treefrog | Gray, green, or brown | Color-changing skin |
| Cope’s Gray Treefrog | Gray, green, or brown | Faster, higher-pitched trill |
| Green Treefrog | Lime green | Pale side stripe |
17. Mountain Chorus Frog
The Mountain Chorus Frog (Pseudacris brachyphona) is restricted to Maryland’s western mountain counties and carries a conservation designation that varies depending on the source consulted.
Important Note: Maryland’s official herpetological checklist lists the mountain chorus frog as State Threatened, while some agency communications have referred to the species as Endangered. Either way, it’s one of the state’s rarer amphibians and worth reporting to state wildlife officials if encountered. The Maryland DNR notes that Maryland is home to three additional species of chorus frog beyond the spring peeper: the upland chorus frog, the New Jersey chorus frog, and the mountain chorus frog. Its raspy, rising call and preference for wooded hillside seeps separate it from its flatland relatives covered next.
18. New Jersey Chorus Frog
The New Jersey Chorus Frog (Pseudacris kalmi) occupies Maryland’s coastal plain and is one of three Pseudacris species that, aside from the spring peeper, round out the state’s chorus frog lineup. It looks nearly identical to the upland chorus frog described next, with a brown or tan body and dark dorsal stripes, and the two are best separated by range rather than appearance since their territories barely overlap in Maryland.
19. Upland Chorus Frog
The Upland Chorus Frog (Pseudacris feriarum) takes over from the New Jersey chorus frog in Maryland’s piedmont and mountain regions. The Maryland State Archives describes it as generally brown or gray in color, measuring 0.8 to 1.4 inches, with a dark triangle pointing backward between the eyes and dark stripes running down the back. Its call, a rough “crreek” repeated in rapid succession, is often compared to running a thumb along the teeth of a comb, and it favors the same grassy wet meadows found in this guide’s coverage of types of frogs in Oklahoma, where several chorus frog relatives share similar open habitat.
20. Spring Peeper
The Spring Peeper (Pseudacris crucifer) is the loudest animal per ounce in Maryland’s wetlands and arguably the most familiar sound of the amphibian year. As a member of the Pseudacris genus, commonly called the chorus frogs, it’s known for singing its song of spring loudly and proudly, usually marked by a distinctive dark “X” across its back. Its high-pitched, single-note peep, repeated dozens of times per minute by a chorus of hundreds, often starts before the last frost and continues into early summer across territory shared with this guide to types of frogs in Connecticut.
21. Eastern Cricket Frog
The Eastern Cricket Frog (Acris crepitans) rounds out Maryland’s list as one of its smallest and most overlooked species, rarely exceeding an inch in length. Its warty skin and irregular dark markings help it blend into mud and vegetation at the water’s edge, where it’s usually detected by its clicking call, often compared to two small stones being tapped together, rather than by sight. It favors the margins of permanent ponds, slow streams, and marshy shorelines across most of the state, rounding out a checklist that spans burrowing spadefoots, booming bullfrogs, and this tiny clicking frog with equal billing.
Twenty-one species packed into one mid-sized state is a reminder of just how much habitat variety Maryland offers, from tidal marsh to mountain seep. Learning a handful of calls and a few key field marks, like the bullfrog’s missing dorsal ridge or the pickerel frog’s square spots, turns most of this list into an identification exercise anyone can do from a porch after dark. For readers curious how Maryland’s lineup stacks up elsewhere, this broader look at how many types of frogs exist worldwide puts the state’s 21 species into global context, while related wildlife like the snakes found across Maryland share many of the same wetland habitats these frogs call home.