As of the 2010 United States Census, there were 41,120 people, 16,519 households, and 10,914 families living in the county. The population density was . There were 22,245 housing units at an average density of . The racial makeup of the county was 73.9% white, 11.4% American Indian, 0.6% Asian, 0.4% black or African American, 0.1% Pacific islander, 10.1% from other races, and 3.5% from two or more races. Those of Hispanic or Latino origin made up 17.6% of the population. In terms of ancestry, 21.4% were German, 12.4% were Irish, 12.2% were English, and 3.6% were American.