Fort Thompson (Lakota: Čunkičakse) is a census-designated place (CDP) in Buffalo County, South Dakota, United States.

Big Bend Dam is located just south of Ft. Thompson and impounds Lake Sharpe.

With such high rates of poverty, unemployment, and other negative social indicators, the living conditions found in the town and county are often compared to a third world nation.

Accounts of the town report rundown neighborhoods with old newspapers, tin foil, or old sheets covering windows of some homes.

A quarter of the residents do not have an automobile and have to walk or bicycle very long distances to work or services in the low density area.