On May 16, 1863, the Battle of Champion's Hill, Mississippi took place. It was the bloodiest action of the Vicksburg Campaign. From the article:
"Battle of Champion Hill Facts & Summary
The Battle of Champion Hill was the largest and bloodiest action of Maj. Gen. Ulysses S. Grant’s Vicksburg Campaign. Following the Union capture of Jackson, Mississippi, Grant's 32,000 advancing Union soldiers met 22,000 Confederates under Maj. Gen. John C. Pemberton in a fierce struggle for a vital crossroads roughly halfway between Vicksburg and Jackson. Pemberton posted his divisions on high ground in a 3-mile line covering the roads from Jackson. Grant's men moved west along the Jackson Road and met Pemberton's men at Champion's Hill. Outflanked, Pemberton stretched his line to hold back the Yankees, advancing all across his front. As the Union soldiers tried to reform and consolidate their gains, they were nearly swept away by a counterattack led by a division of Brig. Gen. John Bowen’s Missourians and Arkansans. Grant ordered more men towards the hill and Bowen’s Confederates were themselves driven off, compelling a general retreat. Confederate Brig. Gen. Lloyd Tilghman was killed while directing a desperate rearguard action that enabled most of the Confederate army to escape towards Vicksburg. The decisive Union victories at Champion Hill and at the Big Black River the next day were instrumental in forcing the Confederates out of the open and into a doomed position inside the fortifications of Vicksburg."