Pursuing John Pemberton’s retreating Confederates from Champion Hill, on May 17, 1863, Federal forces attacked Pemberton’s Confederates on the east bank of the Big Black River. Attacking through waist deep water, Union forces overran the Confederates’ breastworks of cotton bales and an abatis of felled trees to the front, forcing the Confederates in confusion and panic to withdraw across the river.
The retreating Confederates then burned the bridge and steamboat in which they crossed, preventing further Union pursuit. At a loss of 276 casualties, the attacking Union force inflicted 1751 casualties on the Confederates. Fewer than half of the Confederates who had fought at Champion Hill the day before made it into the defenses at Vicksburg. The Battle at Big Black River sealed Vicksburg's fate, bottling up Pemberton’s surviving Confederate forces.