Habitats include creeks, rivers, canals, lakes, oxbows, ponds, reservoirs, marshes, bogs, and swamps; this snake usually inhabits freshwater but also occurs in brackish and saltwater habitats in some areas (Ernst and Ernst 2003, Gibbons and Dorcas 2004). It frequents sunny areas, especially piles of flood-deposited debris, logs, or rocks, at the water's edge. Hibernation sites often are in burrows, among rocks, or in deep crevices, at the water's edge or in uplands near water.

The large range of this species encompasses most of the eastern United States and a relatively small portion of adjacent southeastern Canada, from Maine, southern Quebec, and southern Ontario to Minnesota, extreme southern South Dakota, and eastern Colorado, and south to extreme northern Texas, southern Louisiana, the Florida panhandle, western South Carolina, and North Carolina, at elevations from sea level to around 1,675 m (5,500 feet) (Conant and Collins 1991, Hammerson 1999, Ernst and Ernst 2003, Stebbins 2003, Gibbons and Dorcas 2004).

Many occurrences are in protected areas.