As of the 2010 United States Census, there were 21,376 people, 8,823 households, and 5,575 families in the county. The population density was . There were 15,050 housing units at an average density of . The racial makeup of the county was 84.9% white, 0.9% Asian, 0.6% American Indian, 0.2% black or African American, 0.1% Pacific islander, 11.8% from other races, and 1.5% from two or more races. Those of Hispanic or Latino origin made up 20.0% of the population. In terms of ancestry, 24.1% were German, 18.8% were English, 11.4% were Irish, and 7.9% were American.