 It is bound by the Big Black River, a tributary of the Mississippi River, in the west.As of the 2010 United States Census, there were 19,564 people living in the county, down from its peak in 1940.56.2% were White, 42.0% Black or African American, 0.3% Asian, 0.2% Native American, 0.7% of some other race and 0.6% of two or more races.