Illinois Snakes Pictures and Identification Help

picture of a Smooth Green Snake, part of the Illinois snakes series

Illinois snakes are a collecton of contradictions. On the one hand, the thirty eight species recorded in the state puts it at the above average range for snake diversity. On the other hand, that diversity is a bit misleading because Illinois also lists populations of eleven species as either threatened or endangered.

  • coachwhip (Masticophis flagellum)
  • broad-banded water snake (Nerodia fasciata)
  • eastern massasauga rattlesnake (Sistrurus catenatus)
  • Great Plains rat snake (Elaphe guttata emoryi)
  • Kirtland’s snake (Clonophis kirtlandii)
  • timber rattlesnake (Crotalus horridus)
  • eastern ribbon snake (Thamnophis sauritus)
  • western hognose snake (Heterodon nasicus)
  • Mississippi green water snake (Nerodia cyclopion)
  • lined snake (Tropidoclonion lineatum)
  • flathead snake (Tantilla gracilis)

Most snakes are not adapted to city dwelling, so it’s no surprise that Chicago and the immediate suburbs host only around a dozen snakes. The most common should be no surprise, common garter snakes, northern water snakes, smooth green snakes and fox snakes.

Another half-dozen snake species have been recorded in all of Cook County.

  • Plains garter snake, Thamnophis radix
  • Red-bellied snake, Storeria occipitomaculata
  • Brown snake, Storeria dekayi
  • Queen snake, Regina septemvittata
  • Graham’s crayfish snake, Regina grahamii
  • Milk snake, Lampropeltis triangulum
The top picture shows a smooth green snake.

It’s still up for debate whether there are rattlesnakes in Cook County. Officially people from the Lincoln Park Zoo claim they removed the area’s last population of Eastern Massasauga rattlesnakes for breeding purposes.

Racers and Whipsnakes

picture of a Blue Racer snake
Growing up to eight feet long, the Coluber genus of snakes called Coachwhip snakes, or whipsnakes, get their name from their long, whip like appearance. Snake taxonomy changes.

Black Racer (Coluber constrictor) is the general name for one of the most widespread of all the snakes native to the United States.

In fact eleven different subspecies inhabit almost every state in the lower 48 states. Color is a common name applied to many of the species as well as the Black Racer. Blue Racers, for example are common around the Great Lakes region, including Illinois.

Hog-nosed Snakes

picture of an Eastern Hognose snake
Eastern Hognose snakes (Heterodon platirhinos) are fairly common in areas with sandy soils throughout the state. All Hognose snake species are characterized as having thick bodies that can grow to four feet in length. As the name suggests, a turned up nose is a defining physical feature.

Kingsnakes and Milk Snakes

picture of a an Eastern Black Kingsnake
Three kingsnake species live in Illinois. Two subspecies of the Eastern Milk Snakes (Lampropeltis triangulum), the Black Kingsnake and the Yellow-bellied Kingsnake. Both the Black and Yellow-bellied species live in the southern half of the state. They Yellow-bellied kingsnake is more common.


picture of a Northern Watersnake
The five watersnake species add to Illinois snake diversity, but again aggregate numbers can be deceiving. The Mississippi Green Watersnake and the Southern Watersnake, for example, live in only one or two counties along the southern Mississippi River. Diamonback Watersnake habitat extends up the Mississippi along the western Illinois border.

Plain-bellied Watersnakes are fairly common in the ponds and swamps in the south. The Northern Watersnake (Nerodia sipedon) in the picture is the most common Illinois species.

Physically, water snake bodies grow anywhere from three to six feet in length. Their dark, often blotched skin, helps them blend into their environment.

The venomous Water Moccasin shares a similar habitat and slightly resembles a few water snake species. The shorter and thicker body of the Water Moccasin can normally be used as field identification clues to distinguish between them.

While Water Snake species are not venomous, many species are known to be ill tempered, and quick to bite when startled. Wildlife officials often recommend that boaters avoid drifting under low hanging branches (their favorite basking places) in order to decrease the possibility that the snakes drop in for a ride.

Rat Snakes

picture of a Great Plains Ratsnake
The three species of ratsnakes have a decidedly regional basis. Eastern Foxsnakes are widespread in the north.

Gray ratsnakes are widespread in the south. Like other rat snakes, they grow to be very large, over six feet in length. The common name gray is really a very generic gray. They varies in color with some populations having light gray and others having dark gray bodies. Their bodies also have a pattern.

In terms of size, because adults can grow so large, they become a very imposing snake for the average person to cross paths with. As a result of an encounter, many homeowners inquire into snake control measures when they see these large snakes.

First and foremost, most large rat snakes are as afraid of people as people are afraid of them. In residential areas, they are basically only passing through. There is never a sufficient amount of rodents or other food sources for them.

The picture shows a Great Plains Ratsnake. They are another of the southern Mississippi river snakes, found only in a few counties. The distinct blotches on the body make them easy to identify.

Illinois Garter Snakes

close-up of a common garter snake
The list of Illinois snakes includes four gartersnake species. As previously mentioned the Common Gartersnake range extends across the state.

Two Ribbonsnake species, the eastern and western are recorded. Eastern Ribbon snakes are few and far between, with small populations in the southeast part of the state. Western Ribbonsnakes have a wider range. They can easily be identified by the orange stripe down the back and the light patch in front of the eye.

Plains Gartersnake (Thamnophis radix) live in the prairies of the northern half of the state.

More Colubrid Snakes

Space constrains mean all Illinois snakes can not be presented on a single page. Here’s a quick list of the remaining colubrid snakes. The snake button at the top of the page goes to more snake pictures and information covering most of these snake species.
  • Smooth Earthsnakes (Virginia valeriae)
  • Eastern Wormsnake (Carphophis amoenus)
  • Red bellied Snake (Storeria occipitomaculata)
  • Dekay’s Brownsnake (Storeria dekayi)
  • Ring-necked Snake (Diadophis punctatus)
  • Queen Snake (Regina septemvittata)
  • Flat-headed Snake (Tantilla gracilis)
  • Rough Greensnake (Opheodrys aestivus)
  • Smooth Greensnake (Opheodrys vernalis)
  • Lined Snake (Tropidoclonion lineatum)
  • Western Wormsnake (Carphophis vermis)
  • Kirtland’s Snake (Clonophis kirtlandii)
  • Crayfish snake
  • Mud Snake
  • Bullsnake (Pituophis melanoleucus)

Illinois Venomous Snakes

picture of a Copperhead snake, one of four types of snakes that are poisonous
Last and certainly not least are the four recorded venomous snakes in Illinois. Going back to the beginning of the article, it’s also important to know that the presence of these common eastern spcecies provides more shock value that potential trouble.

The truth is that the vast majority of the state’s residents have little to fear from their presence. According to the Illinois Department of Natural Resources:

Venomous snakes tend to be restricted to specific habitats. Copperheads occur in the southern one-third of Illinois, south of Route 16, and in the lower Illinois River valley. They prefer upland forests or river bluffs with limestone or sandstone outcroppings. Cottonmouths live in swamps and wet bottomlands in southern Illinois, south of Route 13. Timber rattlesnakes may be found in the southern one-fourth of the state (south of Interstate 64), in the lower Illinois River valley, in the Mississippi River valley and in a few other locations. These snakes prefer heavy timber with rock outcrops and bluffs. Eastern massasaugas live in scattered locations within the counties of Madison, Clinton, Piatt, Knox, Warren, Will, Cook, and Lake. Their habitats are prairie wetlands and river floodplains.

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