Southern Illinois took place in Williamson County between 1839 and 1876. This was unusual, as crime was almost non-existent in Illinois during its frontier years prior to this period of lawlessness. In 1858, Abraham Lincoln ran for the U.S. Senate against Stephen A. Douglas. A debate was held in seven towns in Illinois, one being near Jonesboro. Many of the people living in Southern Illinois were first- or second-generation Southerners. Cairo, Illinois, at the southern tip where the Ohio River joins the Mississippi, was of strategic importance. On either side of the rivers were states which, despite remaining in the Union, had
Big Black River (Mississippi) northern border of Claiborne County. The Big Black River and most of its tributaries are silt-filled. The rivers carry large amounts of suspended sediment, resulting mostly from agricultural runoff. These tributaries are slow-flowing muddy streams. However, some are swift-flowing with sandy bottoms. The Battle of Big Black River Bridge, fought during the Battle of Vicksburg, was part of the Vicksburg Campaign in the American Civil War. The size of the Big Black River Basin drainage area is . Its elevation varies from 50 to 650 feet (14 to 198 meters) above sea level. It is long and averages 22 to