Illinois records
Plain-bellied Watersnake in Illinois
HarmlessNerodia erythrogaster

Yes. The Plain-bellied Watersnake has been recorded in 29 Illinois counties. It is non-venomous (harmless). Heavy banded or blotched body, round pupils, and a narrow head — unlike the cottonmouth's broad, blocky head.
Illinois counties with Plain-bellied Watersnake records
29 listedSee the full Plain-bellied Watersnake profile or all snakes in Illinois.