As of the 2010 United States Census, there were 15,387 people, 6,622 households, and 4,343 families residing in the county. The population density was . There were 8,437 housing units at an average density of . The racial makeup of the county was 96.9% white, 0.8% black or African American, 0.3% Asian, 0.3% American Indian, 0.6% from other races, and 1.1% from two or more races. Those of Hispanic or Latino origin made up 2.8% of the population. In terms of ancestry, 40.4% were German, 14.0% were Irish, 11.2% were English, and 10.6% were American.