As of the census of 2000, there were 7,171 people, 2,255 households, and 1,725 families residing in the county. The population density was 7/km² (18/mi²). There were 2,467 housing units at an average density of 2/km² (6/mi²). The racial makeup of the county was 45.77% White, 0.15% Black or African American, 52.03% Native American, 0.06% Asian, 0.77% from other races, and 1.23% from two or more races. 2.43% of the population were Hispanic or Latino of any race. The villages of Emerson, Rosalie, Pender, and Thurston are predominantly white, while the villages of Macy, Walthill, and Winnebago are predominantly Native American.
There were 2,255 households out of which 40.00% had children under the age of 18 living with them, 50.60% were married couples living together, 19.10% had a female householder with no husband present, and 23.50% were non-families. 21.30% of all households were made up of individuals and 10.10% had someone living alone who was 65 years of age or older. The average household size was 3.14 and the average family size was 3.64.
In the county the population was spread out with 36.80% under the age of 18, 8.30% from 18 to 24, 23.90% from 25 to 44, 17.70% from 45 to 64, and 13.20% who were 65 years of age or older. The median age was 30 years. For every 100 females there were 99.40 males. For every 100 females age 18 and over, there were 95.40 males.
The median income for a household in the county was $28,170, and the median income for a family was $30,893. Males had a median income of $24,792 versus $20,481 for females. The per capita income for the county was $10,951. About 19.30% of families and 25.60% of the population were below the poverty line, including 32.60% of those under age 18 and 14.70% of those age 65 or over.