As of the 2010 United States Census, there were 42,481 people, 17,347 households, and 12,128 families living in the county. The population density was . There were 19,227 housing units at an average density of . The racial makeup of the county was 98.6% white, 0.3% American Indian, 0.2% black or African American, 0.2% Asian, 0.1% from other races, and 0.8% from two or more races. Those of Hispanic or Latino origin made up 0.5% of the population. In terms of ancestry, 18.1% were Irish, 16.9% were English, 13.0% were American, and 11.8% were German.