Venomous Reptiles Lurk in Indiana's Waterways, Experts Warn

As of October 6th, 2025, Indiana's lakes and rivers continue to be popular destinations for nature enthusiasts, but they also harbor a surprising number of snake species, both venomous and nonvenomous.

The largest lake in the state, Lake Monroe, is home to several snake species, including the endangered Eastern cottonmouth, a venomous pit viper. Other venomous snakes found near the lake are timber rattlesnakes and copperheads, which prefer forested areas near the water. Nonvenomous species like the plains garter snake and common garter snake are also commonly spotted in the lake's marshy regions.

Further south, Patoka Lake and the Kankakee River are known for their populations of Northern water snakes, a nonvenomous species that enjoys swimming in the deeper parts of the water and basking on the shores. While these snakes are not a threat to humans, visitors are advised to be cautious, as the Northern water snake can be easily confused with the venomous copperhead.

Experts emphasize that most of the snakes found in Indiana's lakes and rivers are not dangerous, but they caution that a few venomous species, such as the Eastern Massasauga rattlesnake in Lake Michigan, do inhabit these areas. As Hoosiers and visitors alike continue to enjoy the state's natural wonders, they are advised to be aware of their serpentine neighbors and give them a wide berth.