Williamstown is a borough in Dauphin County, Pennsylvania, 38 miles (61km) northeast of Harrisburg. Formerly, Anthracite coal mines were here, as well as hosiery mills. The population was 1,433 at the 2000 census. Williamstown is part of the HarrisburgCarlisleMetropolitan Statistical Area. Williamstown is located at 403452N76376W / 40.58111N 76.61833W / 40.58111; -76.61833 (40.581075, -76.618296). According to the United States Census Bureau, the borough has a total area of 0.2 square miles (0.52km2), all of it land.