The Northern Madtom lives in eastern North America, ranging from Ontario south to Mississippi and Tennessee, west to Michigan. It is a globally rare species, with less than 100 known occurrences worldwide. In Canada, the Northern Madtom is found in Lake St. Clair, and the Detroit River, as well as the Thames and Sydenham Rivers. The Ontario population is unusual in that individuals have been caught in deep waters in the Detroit River and Lake St. Clair, whereas typically, the Northern Madtom prefers large creeks and small rivers. It usually avoids extremely silty situations and prefers areas with little cover and a moderate current and rocky substrate.

The Northern Madtom is a member of the Bullhead Catfishes family. It has four pairs of characteristic "barbels" (or whiskers) at the mouth and is usually 51-76 mm long. This species has sharp pectoral spines with poison glands and a single spine is also located on the dorsal fin. The tissue connecting the adipose fin with the caudal fin is deeply notched (fins appear separate). The Northern Madtom is a mottled olive-gray colour dorsally with three dark saddle bands.