On Friday, May 22, 1863, Ulysses Grant ordered a massive assault against Confederate held Vicksburg. Attacking on a three mile front with all available troops, approximately 45, 000 Federals charged the Confederate defenses, moving through deep, narrow ravines; the Confederates—behind a line of high breastworks protected by dirt and logs—rejected the Union attackers.
One breakthrough on the Confederate line was briefly successful before a counterattack closed the breach. Grant’s Federals suffered 3199 casualties, with less than 500 Confederate defenders dead or wounded.
Grant regretted ordering what he later considered to be a suicidal assault of the Confederate line and quickly determined to siege Vicksburg and force the Confederates into surrendering. After this assault, Federal troops began digging approach trenches and artillery positions needed for a siege.