The nightcrawler is native to Europe. It came to North American with settlers, probably between the 17th and 18th centuries, in dirt from nursery stock and with ballast soil.

Different species of earthworms occur throughout the United States in loose, moist soils with high organic matter. Soil moisture is important because the worms breathe through their skin.

Nightcrawlers are found across the northern U.S. and Canada. This area, north of a line from Washington state to New York and running through northern Nebraska, was covered by ice during the last Ice Age glaciation. No native earthworms are found in these areas.

Nightcrawlers are spread into natural areas by fishermen who dump their bait at the end of the day. Following establishment, earthworms spread on their own at a slow rate.