According to the U.S. Census Bureau, the county has a total area of 412 square miles (1,070 km2), of which 399 square miles (1,030 km2) is land and 13 square miles (34 km2) (3.1%) is water. It is the fifth-smallest county in Missouri by area.
As of the census of 2000, there were 8,940 people, 3,911 households, and 2,737 families residing in the county. The population density was 22 people per square mile (9/km²). There were 6,184 housing units at an average density of 16 per square mile (6/km²). The racial makeup of the county was 97.51% White, 0.08% Black or African American, 0.66% Native American, 0.11% Asian, 0.20% from other races, and 1.44% from two or more races. Approximately 0.76% of the population were Hispanic or Latino of any race.
There were 3,911 households out of which 22.00% had children under the age of 18 living with them, 59.90% were married couples living together, 6.70% had a female householder with no husband present, and 30.00% were non-families. 26.50% of all households were made up of individuals and 15.10% had someone living alone who was 65 years of age or older. The average household size was 2.26 and the average family size was 2.70.
In the county the population was spread out with 19.90% under the age of 18, 5.30% from 18 to 24, 19.10% from 25 to 44, 29.70% from 45 to 64, and 26.10% who were 65 years of age or older. The median age was 50 years. For every 100 females there were 96.00 males. For every 100 females age 18 and over, there were 92.70 males.
The median income for a household in the county was $25,346, and the median income for a family was $28,779. Males had a median income of $22,679 versus $17,610 for females. The per capita income for the county was $13,536. About 13.00% of families and 19.70% of the population were below the poverty line, including 32.90% of those under age 18 and 11.00% of those age 65 or over.