Identify The Most Dangerous Snakes In Illinois (With Images)

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Common snakes found in the state of Illinois

Illinois

Copperhead

Agkistrodon contortrix

High Risk

Venomous

50–95 cm (20–37 in)

  • Alabama
  • Arkansas
  • Connecticut
  • Delaware
  • Florida
  • Georgia
  • Illinois
  • Indiana
  • Iowa
  • Kansas
  • Kentucky
  • Louisiana
  • Maryland
  • Massachusetts
  • Mississippi
  • Missouri
  • Nebraska
  • New Jersey
  • New York
  • North Carolina
  • Ohio
  • Oklahoma
  • Pennsylvania
  • South Carolina
  • Tennessee
  • Texas
  • Virginia
  • West Virginia


Cottonmouth

Agkistrodon piscivorus

High Risk

Venomous

65 to 90 cm (26 to 35 in)

  • Alabama
  • Arkansas
  • Florida
  • Georgia
  • Illinois
  • Indiana
  • Kentucky
  • Louisiana
  • Mississippi
  • Missouri
  • North Carolina
  • Oklahoma
  • South Carolina
  • Tennessee
  • Texas
  • Virginia


Timber Rattlesnake

Crotalus horridus

High Risk

Venomous

 91–152 cm (36–60 in)

  • Alabama
  • Arkansas
  • Connecticut
  • Delaware
  • Florida
  • Georgia
  • Illinois
  • Indiana
  • Iowa
  • Kansas
  • Kentucky
  • Louisiana
  • Maryland
  • Massachusetts
  • Mississippi
  • Missouri
  • New Jersey
  • New York
  • North Carolina
  • Ohio
  • Oklahoma
  • Pennsylvania
  • South Carolina
  • Tennessee
  • Texas
  • Virginia
  • West Virginia
  • Wisconsin 


Massasauga

Sistrurus catenatus

High Risk

Venomous

50–95 cm (20–37 in)

  • Arizona
  • Illinois
  • Indiana
  • Iowa
  • Minnesota
  • Missouri
  • New York
  • Ohio
  • Pennsylvania
  • Wisconsin
  • Michigan


Scarlet Snake

Cemophora coccinea

Low Risk

Nonvenomous

14-26 inches (36–66 cm) 

  • Alabama
  • Arkansas
  • Connecticut
  • Delaware
  • Florida
  • Georgia
  • Illinois
  • Indiana
  • Kentucky
  • Louisiana
  • Maryland
  • Massachusetts
  • Mississippi
  • Missouri
  • New Jersey
  • New York
  • North Carolina
  • Oklahoma
  • Pennsylvania
  • South Carolina
  • Tennessee
  • Texas
  • Virginia
  • West Virginia


Kirtland’s Snake

Clonophis kirtlandii

Low Risk

Nonvenomous

30–46 cm (12-18 inches).

  • Illinois
  • Indiana
  • Kentucky
  • Michigan
  • Ohio
  • Pennsylvania


Racer

Coluber constrictor

Low Risk

Nonvenomous

50 -152 cm (20 -60 in)

  • All States except Alaska & Hawaii


Ringneck Snake

Diadophis punctatus

Zero Risk

Nonvenomous

25–38 cm (10–15 in)

  • All States except Alaska & Hawaii


Fox Snake

Pantherophis vulpinus

Low Risk

Nonvenomous

91-182 cm (3 – 6 ft)

  • Illinois
  • Indiana
  • Michigan
  • Missouri
  • Ohio
  • Wisconsin


Mud Snake

Farancia abacura

Low Risk

Nonvenomous

101.6–137 cm (40–54 in)

  • Alabama
  • Arkansas
  • Florida
  • Georgia
  • Illinois
  • Kentucky
  • Louisiana
  • Mississippi
  • Missouri
  • North Carolina
  • Oklahoma
  • South Carolina
  • Tennessee
  • Texas
  • Virginia


Western Hognose Snake

Heterodon nasicus

Low Risk

Nonvenomous

40–50 cm (15–20 in)

  • All States except Alaska & Hawaii


Eastern Hognose Snake

Heterodon platirhinos

Low Risk

Venomous

71 cm (28 in) 

  • Alabama
  • Arkansas
  • Connecticut
  • Delaware
  • Florida
  • Georgia
  • Illinois
  • Indiana
  • Iowa
  • Kansas
  • Kentucky
  • Louisiana
  • Maine
  • Maryland
  • Massachusetts
  • Minnesota
  • Mississippi
  • New Hampshire
  • New Jersey
  • North Carolina
  • Pennsylvania
  • Rhode Island
  • South Carolina
  • Tennessee
  • Texas
  • Virginia
  • West Virginia
  • Wisconsin


Prairie Kingsnake

Lampropeltis calligaster

Low Risk

Nonvenomous

76–102 cm (30–40 in)

  • Alabama
  • Arkansas
  • Florida
  • Georgia
  • Illinois
  • Indiana
  • Iowa
  • Kansas
  • Kentucky
  • Louisiana
  • Michigan
  • Minnesota
  • Mississippi
  • Missouri
  • Nebraska
  • North Carolina
  • North Dakota
  • Ohio
  • South Carolina
  • South Dakota
  • Tennessee
  • Wisconsin


Common Kingsnake

Lampropeltis getula

Low Risk

Nonvenomous

90– 122 cm (35–48 in)

  • Alabama
  • Arizona
  • Arkansas
  • California
  • Colorado
  • Delaware
  • Florida
  • Georgia
  • Illinois
  • Indiana
  • Iowa
  • Kansas
  • Kentucky
  • Louisiana
  • Maryland
  • Mississippi
  • Missouri
  • Nebraska
  • Nevada
  • NewJersey
  • NewMexico
  • NewYork
  • NorthCarolina
  • Ohio
  • Oklahoma
  • Oregon
  • SouthCarolina
  • Tennessee
  • Texas
  • Utah
  • Virginia
  • WestVirginia


Mississippi Green Water Snake

Nerodia cyclopion

Low Risk

Nonvenomous

50–95 cm (20–37 in)

  • Alabama
  • Arkansas
  • Florida
  • Illinois
  • Indiana
  • Kentucky
  • Louisiana
  • Mississippi
  • Missouri
  • Tennessee
  • Texas


Diamondback Water Snake

Nerodia rhombifer

Low Risk

Nonvenomous

76–122 cm (30–48 in)

  • Alabama
  • Arkansas
  • Georgia
  • Illinois
  • Indiana
  • Iowa
  • Kansas
  • Louisiana
  • Mississippi
  • Missouri
  • Oklahoma
  • Tennessee
  • Texas


Northwestern Garter Snake

Thamnophis ordinoides

Low Risk

Nonvenomous

33–97cm (13–38 in)

  • California
  • Oregon


Smooth Green Snake

Opheodrys vernalis

Low Risk

Nonvenomous

36–51 cm (14–20 in)

  • Colorado
  • Illinois
  • Illinois
  • Indiana
  • Iowa
  • Kentucky
  • Michigan
  • Minnesota
  • Missouri
  • New Mexico
  • Ohio
  • Texas
  • Virginia
  • West Virginia
  • Wisconsin
  • Wyoming


Gopher Snake

Pituophis catenifer

Low Risk

Nonvenomous

91–213 cm (36-84 in)

  • Arizona
  • California
  • Idaho
  • Illinois
  • Indiana
  • Iowa
  • Kansas
  • Missouri
  • Montana
  • Nebraska
  • Nevada
  • New Mexico
  • North Dakota
  • Ohio
  • Oklahoma
  • Oregon
  • South Dakota
  • Texas
  • Utah
  • Washington
  • Wisconsin
  • Wyoming


Graham’s Crayfish Snake

Regina grahamii

Low Risk

Nonvenomous

46–71 cm (18–28 in)

  • Arkansas
  • Illinois
  • Iowa
  • Kansas
  • Louisiana
  • Mississippi
  • Missouri
  • Nebraska
  • Oklahoma
  • Texas


Queen Snake

Regina septemvittata

Low Risk

Nonvenomous

17–23 cm (7–9 in)

  • Alabama
  • Connecticut
  • Delaware
  • Florida
  • Georgia
  • Illinois
  • Indiana
  • Kentucky
  • Maine
  • Maryland
  • Massachusetts
  • Michigan
  • Mississippi
  • New Hampshire
  • New Jersey
  • New York
  • North Carolina
  • Ohio
  • Pennsylvania
  • Rhode Island
  • South Carolina
  • Tennessee
  • Vermont
  • Virginia
  • West Virginia
  • Wisconsin


Redbelly Snake

Storeria occipitomaculata

Low Risk

Nonvenomous

4–10 cm (10–25 in)

  • All States except Alaska & Hawaii


Flathead Snake

Tantilla gracilis

Low Risk

Nonvenomous

18–20 cm (7–8 in)

  • Arkansas
  • Illinois
  • Kansas
  • Louisiana
  • Missouri
  • Oklahoma
  • Texas


Plains Garter Snake

Thamnophis radix

Low Risk

Nonvenomous

38–71 cm (15–28 in)

  • Alabama
  • Arkansas
  • Illinois
  • Indiana
  • Iowa
  • Kansas
  • Kentucky
  • Louisiana
  • Michigan
  • Minnesota
  • Mississippi
  • Missouri
  • Nebraska
  • North Dakota
  • Ohio
  • Oklahoma
  • South Dakota
  • Tennessee
  • Texas
  • West Virginia
  • Wisconsin


Eastern Ribbon Snake

Thamnophis sauritus

Low Risk

Nonvenomous

41–89 cm (16–35 in)

  • Alabama
  • Connecticut
  • Delaware
  • Florida
  • Georgia
  • Illinois
  • Indiana
  • Kentucky
  • Maine
  • Maryland
  • Massachusetts
  • Michigan
  • Mississippi
  • New Hampshire
  • New Jersey
  • New York
  • North Carolina
  • Ohio
  • Pennsylvania
  • Rhode Island
  • South Carolina
  • Tennessee
  • Vermont
  • Virginia
  • West Virginia
  • Wisconsin


Common Garter Snake

Thamnophis sirtalis

Low Risk

Nonvenomous

55–137 cm (22–54 in)

  • All States except Alaska & Hawaii


Lined Snake

Tropidoclonion lineatum

Low Risk

Nonvenomous

50–95 cm (20–37 in)

  • Alabama
  • Arkansas
  • Illinois
  • Iowa
  • Kansas
  • Kentucky
  • Louisiana
  • Mississippi
  • Missouri
  • Nebraska
  • Oklahoma
  • Tennessee
  • Texas


Rough Earth Snake

Virginia striatula

Low Risk

Nonvenomous

18–25 cm (7–10 in)

  • Alabama
  • Arkansas
  • Florida
  • Georgia
  • Illinois
  • Indiana
  • Iowa
  • Kansas
  • Kentucky
  • Louisiana
  • Mississippi
  • Missouri
  • North Carolina
  • Oklahoma
  • South Carolina
  • Tennessee
  • Texas
  • Virginia
  • West Virginia


Smooth Earth Snake

Virginia valeriae

Low Risk

Nonvenomous

18–25 cm (7–10 in)

  • Alabama
  • Arkansas
  • Delaware
  • Florida
  • Georgia
  • Illinois
  • Indiana
  • Iowa
  • Kansas
  • Kentucky
  • Louisiana
  • Maryland
  • Mississippi
  • Missouri
  • Nebraska
  • New Jersey
  • North Carolina
  • Ohio
  • Oklahoma
  • Pennsylvania
  • South Carolina
  • Tennessee
  • Texas
  • Virginia
  • West Virginia

For a full list of every venomous and nonvenomous snake found in the USA, check out my full article: Identity 130+ Snake Species From The USA (With Images)