Roberts County is a county in the U.S. state of South Dakota. As of the 2010 United States Census, the population was 10,149. Its county seat is Sisseton. The county was named either for S. G. Roberts of Fargo, North Dakota, or for Solomon Robar, an early local French fur trader. It was created on March 8, 1883, and was fully organized by August 6 of that year. Its boundary was altered one time, in 1885.
Roberts County is at the NE corner of South Dakota. Its east boundary line abuts the west line of the state of Minnesota (across the Bois de Sioux River), and its north boundary line abuts the south boundary line of the state of 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. The terrain slopes to the east; its highest point is on its upper western boundary line, at 2,047′ (624m) ASL.
Roberts County has a total area of 1,136 square miles (2,940 km), of which 1,101 square miles (2,850 km) is land and 35 square miles (91 km) (3.1%) is water. The Traverse Gap is located in Eastern Roberts County along the Minnesota border. The Lake Traverse Indian Reservation is also located in the county.
As of the 2000 United States Census, there were 10,016 people, 3,683 households, and 2,618 families in the county. The population density was 9 people per square mile (4/km²). There were 4,734 housing units at an average density of 4 per square mile (2/km²). The racial makeup of the county was 68.29% White, 0.10% Black or African American, 29.86% Native American, 0.21% Asian, 0.03% from other races, and 1.51% from two or more races. 0.63% of the population were Hispanic or Latino of any race.
There were 3,683 households out of which 33.80% had children under the age of 18 living with them, 53.50% were married couples living together, 11.80% had a female householder with no husband present, and 28.90% were non-families. 26.80% of all households were made up of individuals and 12.40% had someone living alone who was 65 years of age or older. The average household size was 2.66 and the average family size was 3.22.
The county population contained 30.00% under the age of 18, 7.20% from 18 to 24, 23.60% from 25 to 44, 22.20% from 45 to 64, and 17.00% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 98.80 males. For every 100 females age 18 and over, there were 98.20 males.
The median income for a household in the county was $28,322, and the median income for a family was $33,361. Males had a median income of $25,516 versus $19,464 for females. The per capita income for the county was $13,428. About 16.60% of families and 22.10% of the population were below the poverty line, including 30.10% of those under age 18 and 17.40% of those age 65 or over.
As of the 2010 United States Census, there were 10,149 people, 3,823 households, and 2,655 families residing in the county. The population density was 9.2 inhabitants per square mile (3.6/km). There were 4,905 housing units at an average density of 4.5 per square mile (1.7/km). 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.
Roberts County South Dakota neighborhoods include: Alcester, Baltic, Black Hawk, Box Elder, Brandon, Buffalo Ridge, Camp Crook, Canton, Caputa, Central City, Chancellor, Colton, Creighton, Crooks, Custer, Deadwood, Dell Rapids, Elkton, Ellsworth Afb, Garretson, Hartford, Hermosa, Hill City, Howes, Humboldt, Keystone, Lead, Ludlow, Montrose, Nemo, New Underwood, North Sioux City, Owanka, Parker, Quinn, Rapid City, Renner, Rowena, Saint Onge, Scenic, Sherman, Silver City, Sioux Falls, Spearfish, Sturgis, Valley Springs, Wall, Wanblee, Wasta, Whitewood