[3] As of the census[9] of 2000, there were 8,903 people, 3,519 households, and 2,502 families residing in the county.

The racial makeup of the county was 97.43% White, 0.33% Black or African American, 0.55% Native American, 0.11% Asian, 0.35% from other races, and 1.24% from two or more races.

There were 3,519 households, out of which 31.60% had children under the age of 18 living with them, 59.00% were married couples living together, 7.70% had a female householder with no husband present, and 28.90% were non-families.

25.70% of all households were made up of individuals, and 12.30% had someone living alone who was 65 years of age or older.

The Democratic Party predominantly controls politics at the local level in Maries County.

Senator Hillary Clinton (D-New York) received more votes, a total of 844, than any candidate from either party in Maries County during the 2008 presidential primary.