Lancaster is a city in and the county seat of Grant County, Wisconsin, United States. As of the 2000 census, the population was 4,070.
Major G.M. Price, a land speculator, laid out the town in 1837. He was persuaded to name it Lancaster by a relative who migrated from Lancaster, Pennsylvania. At Pleasant Ridge, one of the first African-American communities in Wisconsin was founded by the Shepard family in 1849 and settled in the 1850s. Lancaster was the home of the first governor of Wisconsin, Nelson Dewey.
Lancaster is located at 42°50′55″N 90°42′38″W / 42.848505°N 90.710430°W / 42.848505; -90.710430 (42.848505, -90.710430). Lancaster is located in the unglaciated "Driftless Area" of southwest Wisconsin whose topography is strikingly different from that of the rest of the state.