Illinois records
Eastern Massasauga in Illinois
VenomousSistrurus catenatus

Yes. The Eastern Massasauga has been recorded in 13 Illinois counties. It is venomous. Stout, dark-blotched body, nine large scales on the crown, and a small rattle.
If you are bitten
Rattlesnake bites are medically serious. Expect intense pain, rapid swelling, and bruising. Stay calm, keep the bitten limb still and roughly level with the heart, remove rings and tight clothing, and get to an emergency room immediately. Do NOT apply a tourniquet, cut the wound, apply ice, or try to suck out venom. Call Poison Control at 1-800-222-1222 or 911 in the US, or your local emergency number. (Source: CDC.)
Illinois counties with Eastern Massasauga records
13 listedSee the full Eastern Massasauga profile or all snakes in Illinois.