As of the census of 2000, there were 15,301 people, 6,644 households, and 4,458 families residing in the county. The population density was 8 people per square mile (3/km²). There were 14,168 housing units at an average density of 8 per square mile (3/km²). The racial makeup of the county was 96.41% White, 0.23% Black or African American, 2.28% Native American, 0.20% Asian, 0.02% Pacific Islander, 0.16% from other races, and 0.71% from two or more races. 0.60% of the population were Hispanic or Latino of any race. 29.5% were of German, 14.3% Norwegian, 13.0% Swedish, 6.2% Irish, 5.3% United States or American and 5.2% Finnish ancestry.
There were 6,644 households out of which 22.60% had children under the age of 18 living with them, 57.50% were married couples living together, 6.30% had a female householder with no husband present, and 32.90% were non-families. 28.70% of all households were made up of individuals and 14.00% had someone living alone who was 65 years of age or older. The average household size was 2.28 and the average family size was 2.76.
In the county the population was spread out with 20.90% under the age of 18, 5.50% from 18 to 24, 21.60% from 25 to 44, 29.10% from 45 to 64, and 23.00% who were 65 years of age or older. The median age was 46 years. For every 100 females there were 101.60 males. For every 100 females age 18 and over, there were 99.90 males.
The median income for a household in the county was $31,139, and the median income for a family was $37,290. Males had a median income of $31,604 versus $20,633 for females. The per capita income for the county was $17,848. About 8.20% of families and 11.60% of the population were below the poverty line, including 15.50% of those under age 18 and 11.00% of those age 65 or over.
On ePodunk : Aitkin County & Aitkin Cty. ancestry