It is named in honor of U.S. General Jacob Brown, who defeated the British at the Battle of Sackett's Harbor in 1813.

[4] As of the 2010 United States census, there were 6,937 people, 2,099 households, and 1,346 families living in the county.

[13] The Western Illinois Correctional Center, a state prison 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.

The county is located in the 47th district of the Illinois Senate, and is currently represented by Republican Jil Tracy.

This region was opposed both to southern plantation owners and to anti-slavery Yankees and consequently voted against the majority of people in their state.