Richmond is a town in Sagadahoc County, Maine, United States. The population was 3,522 at the 2020 census. It is part of the Portland–South Portland–Biddeford, Maine metropolitan statistical area, situated at the head of Merrymeeting Bay.

Sagadahoc County is a county located in the U.S. state of Maine. As of the 2020 census, the population was 36,699. Its county seat is Bath. In geographic area, it is the smallest county in Maine.