[3] It is named for Asa and Eli Mitchell, two early settlers and soldiers in the Texas Revolution.

According to the U.S. Census Bureau, the county has a total area of 916 square miles (2,370 km2), of which 911 sq mi (2,360 km2) are land and 4.8 sq mi (12 km2) (0.5%) are covered by water.

As of the census[10] of 2000, 9,698 people, 2,837 households, and 1,997 families resided in the county.

Of the 2,837 households, 30.60% had children under the age of 18 living with them, 55.60% were married couples living together, 11.40% had a female householder with no husband present, and 29.60% were not families; 27.50% of all households were made up of individuals, and 15.50% had someone living alone who was 65 years of age or older.

The median income for a household in the county was $25,399, and for a family was $31,481.