Illinois
Snakes in Williamson County
13 species have been documented here, 1 of them venomous.
Venomous snakes in Williamson County
Full guide & what to do if bitten →
Eastern CopperheadAgkistrodon contortrixVenomousHeavy body, triangular head, vertical pupils, and a heat-sensing pit between each eye and nostril.
Every snake recorded in Williamson County
Common Watersnake
Nerodia sipedon
Harmless
Gray Ratsnake
Pantherophis spiloides
Harmless
Eastern Copperhead
Agkistrodon contortrix
Venomous
Common Garter Snake
Thamnophis sirtalis
Harmless
Prairie Kingsnake
Lampropeltis calligaster
Harmless
Rough Greensnake
Opheodrys aestivus
Harmless
Diamondback Watersnake
Nerodia rhombifer
Harmless
Eastern Milksnake
Lampropeltis triangulum
Harmless
DeKay's Brownsnake
Storeria dekayi
Harmless
North American Racer
Coluber constrictor
Harmless
Plain-bellied Watersnake
Nerodia erythrogaster
Harmless
Eastern Hognose Snake
Heterodon platirhinos
Harmless
Black Kingsnake
Lampropeltis nigra
Harmless
Compiled from verified GBIF & iNaturalist observations. Informational only.
Snakes in Williamson County: FAQ
- Are there venomous snakes in Williamson County, Illinois?
- Yes. 1 venomous snake species has verified records in Williamson County, Illinois, including Eastern Copperhead. Most snakes in Williamson County, Illinois, however, are harmless.
- How many snake species live in Williamson County, Illinois?
- 10+ snake species have verified records in Williamson County, Illinois, of which 1 is venomous.
- What is the most commonly seen snake in Williamson County, Illinois?
- The Common Watersnake is the most frequently reported snake in Williamson County, Illinois, based on verified wildlife observations.
- What should I do if I see a venomous snake in Williamson County, Illinois?
- Keep your distance and do not try to catch or kill it. Most bites happen when people handle or corner a snake. If someone is bitten, contact local emergency services or poison control immediately.