In 2019, Sully County, SD had a population of 1.31k people with a median age of 46.8 and a median household income of $62,153. Between 2018 and 2019 the population of Sully County, SD declined from 1,331 to 1,305, a −1.95% decrease and its median household income declined from $64,028 to $62,153, a −2.93% decrease.
The 5 largest ethnic groups in Sully County, SD are White (Non-Hispanic) (96%), Two+ (Non-Hispanic) (1.61%), American Indian & Alaska Native (Non-Hispanic) (1.07%), Two+ (Hispanic) (0.996%), and American Indian & Alaska Native (Hispanic) (0.307%). 0% of the households in Sully County, SD speak a non-English language at home as their primary language, and 100% of the residents in Sully County, SD are U.S. citizens.
In 2019, the median property value in Sully County, SD was $144,100, and the homeownership rate was 85.9%. Most people in Sully County, SD drove alone to work, and the average commute time was 11.1 minutes. The average car ownership in Sully County, SD was 3 cars per household.