According to the Illinois Department of Natural Resources, there are four venomous snakes native to Illinois. All are a part of the snake family called Crotalinae: The copperhead –can be found in the southern part of Illinois, south of Route 16. The cottonmouth (also known as the water moccasin) – live in swamps and wet bottomlands in southern Illinois, south of Route 13. The timber rattlesnake – can be found in the southern part of the state (south of Interstate 64), mostly in the Illinois River Valley and the Mississippi River Valley. The eastern massasauga – can be found scattered within the counties of Madison, Clinton, Piatt, Knox, Warren, Will, Cook, and Lake. Symptoms Envenomation by snakes in the Crotalinae group can inflict significant injury and potentially life threatening symptoms: Local effects: rapid progressing swelling, severe pain, redness, a broken blood vessel or bruised appearance, large vesicles, bleeding and tissue ulceration or cell death. Systemic effects: tingling of the mouth, hands and feet, a drop in blood pressure or shock, respiratory failure, weakness and sweating, nausea and vomiting, and blood clotting abnormalities which may lead to profound bleeding. We recommend that anyone with a known or suspected bite by one of these four snakes be immediately transported to the nearest emergency room. Treatment may include intravenous fluids, wound care, frequent lab tests, and possibly administration of an anti-venom specific for Crotalinae snakes or blood products. A variety of non-poisonous snakes also inhabit Illinois. And while they are not venomous, they will bite if provoked. Non-poisonous snakes in Illinois include the black rat snake, prairie king snake, bull snake, and common garter snake.