Fort Pierre is a city in Stanley County, South Dakota, United States. It is part of the Pierre, South Dakota micropolitan area and the county seat of Stanley County. The population was 2,078 at the 2010 census.
The settlement of Fort Pierre developed around an 1832 trading post and fort situated on the west bank of the Missouri River, near the confluence with its tributary Bad River. But another American-owned trading post had been operating nearby since 1817, and in 2017 the city celebrated its bicentennial of continuous permanent settlement.