As of July 2002, its population was estimated at 16,897, a loss of nearly 350 people from the 2000 census figure of 17,243.
As of the census of 2000, there were 17,243 people, 6,677 households, and 4,613 families residing in the county. The population density was 12/km² (30/sq mi). There were 8,480 housing units at an average density of 6/km² (15/sq mi). The racial makeup of the county was 97.31% White, 1.35% Black or African American, 0.21% Native American, 0.26% Asian, 0.01% Pacific Islander, 0.17% from other races, and 0.68% from two or more races. 0.75% of the population were Hispanic or Latino of any race. 33.6% were of German, 16.0% Norwegian, 11.4% Irish, 7.2% Czech, 7.2% English and 6.4% United States or American ancestry.
There were 6,677 households out of which 31.60% had children under the age of 18 living with them, 56.70% were married couples living together, 8.40% had a female householder with no husband present, and 30.90% were non-families. 26.70% of all households were made up of individuals and 13.00% had someone living alone who was 65 years of age or older. The average household size was 2.48 and the average family size was 3.00.
In the county, the population was spread out with 26.20% under the age of 18, 8.10% from 18 to 24, 25.00% from 25 to 44, 24.80% from 45 to 64, and 16.00% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 102.20 males. For every 100 females age 18 and over, there were 99.30 males.