2000 26,523 1990 24,616 1980 24,398 1970 21,138 1960 20,641 1950 18,763 1940 18,898 1930 18,078 1920 18,694 1910 19,452 1900 19,881 1890 19,350 1880 21,627 1870 20,977 1860 19,054 1850 14,820 1840 10,392 1830 3,989 1820 1,822
As of the census of 2000, there were 26,523 people, 9,842 households, and 7,273 families residing in the county. The population density was 59 people per square mile (23/km²). There were 10,482 housing units at an average density of 24 per square mile (9/km²). The racial makeup of the county was 98.30% White, 0.05% Black or African American, 0.35% Native American, 0.36% Asian, 0.54% from other races, and 0.41% from two or more races. 0.93% of the population were Hispanic or Latino of any race. 46.6% were of German, 19.5% American, 9.5% Irish and 8.2% English ancestry according to Census 2000.
There were 9,842 households out of which 36.70% had children under the age of 18 living with them, 61.30% were married couples living together, 8.70% had a female householder with no husband present, and 26.10% were non-families. 22.70% of all households were made up of individuals and 10.70% had someone living alone who was 65 years of age or older. The average household size was 2.66 and the average family size was 3.13.
In the county the population was spread out with 28.10% under the age of 18, 7.70% from 18 to 24, 28.90% from 25 to 44, 22.00% from 45 to 64, and 13.40% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 96.50 males. For every 100 females age 18 and over, there were 94.00 males.
The median income for a household in the county was $41,426, and the median income for a family was $47,019. Males had a median income of $34,055 versus $23,610 for females. The per capita income for the county was $17,559. About 6.30% of families and 7.50% of the population were below the poverty line, including 8.00% of those under age 18 and 8.70% of those age 65 or over.