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.

Bath is a city in Sagadahoc County, Maine, United States. Bath is included in the Brunswick micropolitan. The population was 8,766 at the 2020 census. It is the county seat of Sagadahoc County, which includes one city and 10 towns. The city is popular with tourists, many drawn by its 19th-century architecture. It is home to the Bath Iron Works and Heritage Days Festival, held annually on the Fourth of July weekend. It is commonly known as "The City of Ships" because of all the sailing ships that were built in the Bath shipyards. Bath is part of the Portland-South Portland-Biddeford metropolitan statistical area.