2000 24,555 1990 23,645 1980 23,841 1970 22,738 1960 20,019 1950 18,218 1940 17,722 1930 17,308 1920 17,813 1910 18,793 1900 19,518 1890 19,277 1880 19,779 1870 19,053 1860 17,294 1850 15,107 1840 12,171 1830 5,887
As of the census of 2000, there were 24,555 people, 9,389 households, and 6,882 families residing in the county. The population density was 66 people per square mile (25/km²). There were 9,992 housing units at an average density of 27 per square mile (10/km²). The racial makeup of the county was 98.50% White, 0.05% Black or African American, 0.11% Native American, 0.72% Asian, 0.01% Pacific Islander, 0.10% from other races, and 0.52% from two or more races. 0.54% of the population were Hispanic or Latino of any race. 35.1% were of German, 23.3% American, 12.3% English and 9.0% Irish ancestry according to Census 2000.
There were 9,389 households out of which 34.10% had children under the age of 18 living with them, 60.10% were married couples living together, 9.20% had a female householder with no husband present, and 26.70% were non-families. 22.80% of all households were made up of individuals and 9.60% had someone living alone who was 65 years of age or older. The average household size was 2.58 and the average family size was 3.03.
In the county the population was spread out with 26.30% under the age of 18, 8.90% from 18 to 24, 29.30% from 25 to 44, 22.30% from 45 to 64, and 13.30% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 97.60 males. For every 100 females age 18 and over, there were 94.40 males.
The median income for a household in the county was $40,401, and the median income for a family was $46,453. Males had a median income of $31,790 versus $24,688 for females. The per capita income for the county was $18,582. About 6.60% of families and 9.30% of the population were below the poverty line, including 13.40% of those under age 18 and 8.10% of those age 65 or over.