In the fall of 1859, John Brown launched a raid on the federal arsenal at Harpers Ferry, Virginia, and in so doing arguably fired the first salvo of the Civil War. That his raid occurred in the border area between North and South should come as no surprise because it was in that area where Americans were the most divided. Citizens across the border state region–that area that comprised the lower North and upper South–soon found themselves caught between two hostile sections. Based on an analysis of letters, journals, newspapers, and public documents, this dissertation is a study of one portion of that border region, the central Ohio River Valley, during the momentous years between Brown’s raid and the early weeks of 1862, when Indiana Senator Jesse Bright was expelled from the United States Senate for treasonous behavior. Citizens who lived in the river counties between Cincinnati and Louisville shared important economic, cultural, and socio-political views that united them and created a regional bond capable of withstanding the centrifugal pull of sectionalism despite the omnipresent influence of slavery. These trans-river bonds moderated their response to secession and reinforced their Unionist proclivities. Their fidelity to the Union strengthened Abraham Lincoln’s hand and helped to insure that the Union would endure.