As of the 2010 census, there were 37,220 people, 11,120 households, and 8,188 families living in the county. The population density was . There were 12,980 housing units at an average density of . The racial makeup of the county was 72.1% white, 14.4% American Indian, 1.8% black or African American, 0.5% Asian, 0.1% Pacific islander, 8.2% from other races, and 2.8% from two or more races. Those of Hispanic or Latino origin made up 30.4% of the population. In terms of ancestry, 16.1% were English, 9.2% were German, 6.9% were Irish, and 4.3% were American.