According to the U.S. Census Bureau, the county has a total area of 888 square miles (2,299.9 km2), of which 873 square miles (2,261.1 km2) is land and 15 square miles (38.8 km2) (1.71%) is water. The highest point in the county is at the foot of the Basswood Lookout Tower west of Summit Lake (elev:1857')
There were 8,452 households out of which 29.40% had children under the age of 18 living with them, 56.70% were married couples living together, 8.20% had a female householder with no husband present, and 31.20% were non-families. 26.70% of all households were made up of individuals and 13.60% had someone living alone who was 65 years of age or older. The average household size was 2.42 and the average family size was 2.93.
In the county, the population was spread out with 24.40% under the age of 18, 6.50% from 18 to 24, 26.00% from 25 to 44, 24.30% from 45 to 64, and 18.80% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 98.50 males. For every 100 females age 18 and over, there were 95.60 males.