Illinois snakes: ID chart
40 snakes, 4 venomous (listed first). Last checked November 3, 2026.
The 4 venomous snakes come first: Eastern Copperhead, Eastern Massasauga, Northern Cottonmouth, Timber Rattlesnake. The rest follow from A to Z, each with a photo where we have one and a short note on where it lives in Illinois. The chart prints on letter or A4 paper; on screen, open any name on the Illinois snakes page for photos, range and sources.
Eastern Copperhead
Agkistrodon contortrix
Venomous
Copperheads occur in the southern one-third of Illinois, south of Route 16 and in the lower Illinois River …
Eastern Massasauga
Sistrurus catenatus
Venomous
Massasaugas live in scattered locations within the counties of Madison, Clinton, Piatt, Knox, Warren, Will …
Northern Cottonmouth
Agkistrodon piscivorus
Venomous
Cottonmouths live in swamps and wet bottomlands in southern Illinois, south of Route 13.
Timber Rattlesnake
Crotalus horridus
Venomous
Timber rattlesnakes may be found in the southern one-fourth of the state (south of Interstate 64), in the …
Coachwhip
Coluber flagellum
Non-venomous
Common Watersnake
Nerodia sipedon
Non-venomous
Common Wormsnake
Carphophis amoenus
Non-venomous
DeKay’s Brownsnake
Storeria dekayi
Non-venomous
Diamond-backed Watersnake
Nerodia rhombifer
Non-venomous
Eastern Foxsnake
Pantherophis vulpinus
Non-venomous
Eastern Hog-nosed Snake
Heterodon platirhinos
Non-venomous
Eastern Ribbonsnake
Thamnophis sauritus
Non-venomous
Flat-headed Snake
Tantilla gracilis
Non-venomous
Gophersnake
Pituophis catenifer
Non-venomous
Graham’s Crayfish Snake
Regina grahamii
Non-venomous
Great Plains Ratsnake
Pantherophis emoryi
Non-venomous
Kirtland’s Snake
Clonophis kirtlandii
Non-venomous
Lined Snake
Tropidoclonion lineatum
Non-venomous
Mississippi Green Watersnake
Nerodia cyclopion
Non-venomous
North American Racer
Coluber constrictor
Non-venomous
Plain-bellied Watersnake
Nerodia erythrogaster
Non-venomous
Plains Gartersnake
Thamnophis radix
Non-venomous
Prairie Kingsnake
Lampropeltis calligaster
Non-venomous
Queensnake
Regina septemvittata
Non-venomous
Red-bellied Mudsnake
Farancia abacura
Non-venomous
Red-bellied Snake
Storeria occipitomaculata
Non-venomous
Ring-necked Snake
Diadophis punctatus
Non-venomous
Scarletsnake
Cemophora coccinea
Non-venomous
Smooth Earthsnake
Virginia valeriae
Non-venomous
Smooth Greensnake
Opheodrys vernalis
Non-venomous
Southern Watersnake
Nerodia fasciata
Non-venomous
Western Foxsnake
Pantherophis ramspotti
Non-venomous
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Western Ribbonsnake
Thamnophis proximus
Non-venomous
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Western Wormsnake
Carphophis vermis
Non-venomous
A picture cannot confirm what an animal is or that it is safe. Never handle a wild animal. Sources: Wild About Illinois Snakes! (species gallery by family) (IDNR); Scarletsnake (Field Guide to Amphibians and Reptiles of Illinois) (Illinois Natural History Survey (INHS), Prairie Research Institute, University of Illinois Urbana-Champaign); North American Racer (Field Guide to Amphibians and Reptiles of Illinois) (Illinois Natural History Survey (INHS), Prairie Research Institute, University of Illinois Urbana-Champaign); Prairie Kingsnake (Field Guide to Amphibians and Reptiles of Illinois) (Illinois Natural History Survey (INHS), Prairie Research Institute, University of Illinois Urbana-Champaign); Eastern Kingsnake (Field Guide to Amphibians and Reptiles of Illinois) (Illinois Natural History Survey (INHS), Prairie Research Institute, University of Illinois Urbana-Champaign); Eastern Milksnake (Field Guide to Amphibians and Reptiles of Illinois) (Illinois Natural History Survey (INHS), Prairie Research Institute, University of Illinois Urbana-Champaign); and others listed on the web page. stateswildlife.com/illinois/snakes/