As of the 2010 United States Census, there were 20,978 people, 8,558 households, and 6,025 families living in the county. The population density was . There were 10,202 housing units at an average density of . The racial makeup of the county was 92.7% white, 1.4% American Indian, 0.5% Asian, 0.2% black or African American, 0.1% Pacific islander, 3.2% from other races, and 2.0% from two or more races. Those of Hispanic or Latino origin made up 7.0% of the population. In terms of ancestry, 20.7% were German, 14.6% were English, 12.6% were Irish, and 6.2% were American.