As of the 2010 United States Census, there were 16,729 people, 6,782 households, and 4,823 families residing in the county. The population density was . There were 7,269 housing units at an average density of . The racial makeup of the county was 98.0% white, 0.3% black or African American, 0.3% Asian, 0.2% American Indian, 0.2% from other races, and 0.9% from two or more races. Those of Hispanic or Latino origin made up 1.0% of the population. In terms of ancestry, 26.1% were German, 21.9% were American, 15.2% were English, and 13.4% were Irish.