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.

The city of Portland, Maine, is the hub city of a metropolitan area in southern Maine. The region is commonly known as Greater Portland or the Portland metropolitan area. For statistical purposes, the U.S. federal government defines three different representations of the Portland metropolitan area. The Portland–South Portland, Maine, metropolitan statistical area is a region consisting of three counties in Maine, anchored by the city of Portland and the smaller city of South Portland. As of the 2020 census, the MSA had a population of 551,740. A larger combined statistical area (CSA), the Portland–Lewiston–South Portland combined statistical area, is defined as the combination of this metropolitan statistical area (MSA) with the adjacent Lewiston–Auburn MSA. The CSA comprises four counties in southern Maine. The Portland–South Portland metropolitan New England city and town area is defined on the basis of cities and towns rather than entire counties. It consists of most of Cumberland and York counties plus the town of Durham in Androscoggin County. The Greater Portland area has emerged as an important center for the creative economy, which is also bringing gentrification.