Brown County is a county located in the U.S. state of Illinois. As of the 2010 census, the population was 6,937. Its county seat is Mount Sterling.
According to the U.S. Census Bureau, the county has a total area of 307 square miles (800 km), of which 306 square miles (790 km) is land and 1.6 square miles (4.1 km) (0.5%) is water. The Illinois River flows along part of the county’s eastern border.
As of the 2010 United States Census, there were 6,937 people, 2,099 households, and 1,346 families residing in the county. The population density was 22.7 inhabitants per square mile (8.8/km). There were 2,462 housing units at an average density of 8.1 per square mile (3.1/km). The racial makeup of the county was 76.1% white, 18.5% black or African American, 0.2% Asian, 0.2% American Indian, 4.4% from other races, and 0.6% from two or more races. Those of Hispanic or Latino origin made up 5.8% of the population. In terms of ancestry, 25.5% were German, 15.6% were American, 12.7% were Irish, and 6.1% were English.
Of the 2,099 households, 28.4% had children under the age of 18 living with them, 51.3% were married couples living together, 8.6% had a female householder with no husband present, 35.9% were non-families, and 32.2% of all households were made up of individuals. The average household size was 2.30 and the average family size was 2.88. The median age was 37.3 years.
The median income for a household in the county was $38,696 and the median income for a family was $50,341. Males had a median income of $34,648 versus $27,288 for females. The per capita income for the county was $17,133. About 9.9% of families and 12.0% of the population were below the poverty line, including 15.0% of those under age 18 and 9.2% of those age 65 or over.
The Illinois state prison, Western Illinois Correctional Center, located south east of Mount Sterling, has an average daily population of 2,066. The all-male population and racial makeup of the prison is so large, compared to the rest of the county, that it skews the census demographic data. This is evidenced by the lopsided age pyramid.