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.

Bath Iron Works (BIW) is a major United States shipyard located on the Kennebec River in Bath, Maine, founded in 1884 as Bath Iron Works, Limited. Since 1995, Bath Iron Works has been a subsidiary of General Dynamics, one of the world's largest defense companies. BIW has built private, commercial, and military vessels, most of which have been ordered by the United States Navy.