The banded killifish is widely distributed throughout eastern North America, ranging from the Pee Dee River, South Carolina to Newfoundland; also found in southern Pennsylvania, northeastern Nebraska, and northern Illinois, and north to St. Lawrence-Great Lakes and Mississippi River basins from Manitoba to Quebec. The eastern subspecies is found on the Atlantic Slope, and the western subspecies in the rest of its range. Westward expansion by the eastern subspecies may be the result of introductions as bait or aquarium fish into novel waterbodies, climate change expanding favorable habitat, or a higher pollution tolerance compared to the western subspecies.