| County: | Roberts County |
| State: | South Dakota |
| Ex Image: | Roberts County Courthouse.jpg |
| Founded: | March 8, 1883 (organized)[1] August 6, 1883 (organized) |
| Seat Wl: | Sisseton |
| Largest City Wl: | Sisseton |
| Area Total Sq Mi: | 1136 |
| Area Land Sq Mi: | 1101 |
| Area Water Sq Mi: | 35 |
| Area Percentage: | 3.1 |
| Population As Of: | 2020 |
| Population Total: | 10280 |
| Pop Est As Of: | 2023 |
| Population Est: | 10206 |
| Density Sq Mi: | auto |
| Time Zone: | Central |
| Web: | http://roberts.sdcounties.org/ |
| Named For: | S. G. Roberts |
| District: | At-large |
Roberts County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 10,280.[2] Its county seat is Sisseton.[3] The county was named either for S. G. Roberts of Fargo, North Dakota, or for Solomon Robar, an early local French fur trader.[1] It was created on March 8, 1883, and fully organized by August 6 of that year. Its boundary was altered once, in 1885.[4]
Roberts County is at South Dakota's northeastern corner. Its eastern boundary abuts Minnesota (across the Bois de Sioux River), and its northern boundary abuts North Dakota. The Cottonwood Slough flows southward, draining the upper portion of the county into the River. The terrain consists of rolling hills, devoted to agriculture.[5] The terrain slopes to the east; its highest point is on its upper western boundary line, at 2047feet ASL.[6]
Roberts County has an area of, of which is land and (3.1%) is water.[7] The Traverse Gap is in eastern Roberts County along the Minnesota border. The Lake Traverse Indian Reservation covers most of the county.
As of the 2020 census, there were 10,280 people, 3,844 households, and 2,568 families residing in the county.[8] The population density was . There were 4,788 housing units.
As of the 2010 census, there were 10,149 people, 3,823 households, and 2,655 families residing in the county. The population density was . There were 4,905 housing units at an average density of 4.5/mi2. The racial makeup of the county was 61.7% white, 34.5% American Indian, 0.2% Asian, 0.1% black or African American, 0.4% from other races, and 3.0% from two or more races. Those of Hispanic or Latino origin made up 1.2% of the population. In terms of ancestry, 31.3% were German, 19.2% were Norwegian, 6.3% were Irish, and 3.8% were American.
Of the 3,823 households, 34.4% had children under the age of 18 living with them, 49.1% were married couples living together, 13.4% had a female householder with no husband present, 30.6% were non-families, and 27.3% of all households were made up of individuals. The average household size was 2.58 and the average family size was 3.11. The median age was 39.5 years.
The median income for a household in the county was $37,708 and the median income for a family was $46,146. Males had a median income of $34,080 versus $28,423 for females. The per capita income for the county was $19,825. About 14.3% of families and 20.0% of the population were below the poverty line, including 33.9% of those under age 18 and 11.0% of those age 65 or over.
School districts include:[9]