Lancaster (local pronunciation /ˈlæŋkəstər/ LANG-kəs-tər or even /ˈlæŋkstər/ LANGK-stər) is a city in Fairfield County, Ohio, United States. As of the 2010 census, the city population was 38,780. It is located near the Hocking River, approximately 33 miles (53 km) southeast of Columbus, Ohio. It is the county seat of Fairfield County. The current mayor of Lancaster is Republican David S. Smith, who took office in January 2004. In November 2011, Smith won reelection to a third four-year term ending December 31, 2015.