Southern Maryland, also referred to as SoMD, is a geographical, cultural and historic region in Maryland composed of the state's southernmost counties on the Western Shore of the Chesapeake Bay. According to the state of Maryland, the region includes all of Calvert, Charles, and St. Mary's counties. As of the 2020 Census, the region had a population of 373,177. The largest community in Southern Maryland is Waldorf, with a population of 81,410 as of the 2020 Census.