Clark SD

As of the census  of 2010, there were 1,139 people, 552 households, and 306 families residing in the city. The population density was 889.8 inhabitants per square mile (343.6/km2). There were 627 housing units at an average density of 489.8 per square mile (189.1/km2). The racial makeup of the city was 98.5% White, 0.1% African American, 0.2% Asian, 0.3% from other races, and 1.0% from two or more races. Hispanic or Latino of any race were 1.4% of the population.

There were 552 households of which 19.2% had children under the age of 18 living with them, 46.4% were married couples living together, 6.0% had a female householder with no husband present, 3.1% had a male householder with no wife present, and 44.6% were non-families. 40.6% of all households were made up of individuals and 24.1% had someone living alone who was 65 years of age or older. The average household size was 1.99 and the average family size was 2.68.

The median age in the city was 51.5 years. 18.8% of residents were under the age of 18; 3.7% were between the ages of 18 and 24; 20.1% were from 25 to 44; 24.8% were from 45 to 64; and 32.7% were 65 years of age or older. The gender makeup of the city was 47.1% male and 52.9% female.