The Arkansas River forms part of the county's northeastern boundary. Two of its tributaries, Red Rock Creek in the north and by Black Bear Creek in the south, drain the county before emptying into the Arkansas River. As of the census of 2000, there were 11,411 people, 4,504 households, and 3,211 families residing in the county. The population density was 6/km² (16/mi²). There were 5,082 housing units at an average density of 3/km² (7/mi²). The racial makeup of the county was 86.44% White, 1.58% Black or African American, 7.57% Native American, 0.33% Asian, 0.03% Pacific Islander, 0.65% from other races, and 3.40% from two or more races. 1.80% of the population were Hispanic or Latino of any race. There were 4,504 households out of which 32.00% had children under the age of 18 living with them, 59.00% were married couples living together, 8.40% had a female householder with no husband present, and 28.70% were non-families. 25.50% of all households were made up of individuals and 11.20% had someone living alone who was 65 years of age or older. The average household size was 2.47 and the average family size was 2.97. In the county, the population was spread out with 25.50% under the age of 18, 7.90% from 18 to 24, 27.50% from 25 to 44, 23.90% from 45 to 64, and 15.20% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 97.40 males. For every 100 females age 18 and over, there were 96.00 males. The median income for a household in the county was $33,968, and the median income for a family was $40,180. Males had a median income of $32,224 versus $21,235 for females. The per capita income for the county was $17,022. About 9.60% of families and 12.80% of the population were below the poverty line, including 16.40% of those under age 18 and 11.00% of those age 65 or over. The county economy has largely been based on agriculture and cattle. Wheat was the major crop, although alfalfa, oats, corn, and barley have also been important.