Clark County is one of 66 counties in South Dakota. The estimated population in 2004 was 3,953. In 2002, the per capita personal income in Clark County was $25,753. This was an increase of 16.9 per cent from 1997. The 2002 figure was 83 per cent of the national per capita income, which was $30,906. Its county seat is Clark. The communities in Clark County include Ash, Blaine, Bradley, Clark, Collins, Cottonwood, Darlington, Day, Eden and Elrod. Included in Clark Counties places of interest are the Ingalls House, Leavenworth Monument, Mount Rushmore National Memorial, Surveyors House (Home of Laura Ingalls Wilder) and Wounded Knee Battlefield.