As of the 2010 United States Census, there were 138,494 people, 54,200 households, and 37,316 families living in the county. The population density was . There were 63,177 housing units at an average density of . The racial makeup of the county was 94.5% white, 1.3% American Indian, 0.7% Asian, 0.3% black or African American, 0.1% Pacific islander, 0.8% from other races, and 2.4% from two or more races. Those of Hispanic or Latino origin made up 3.8% of the population. In terms of ancestry, 25.9% were German, 15.2% were Irish, 13.9% were English, 12.5% were American, and 6.7% were Norwegian.