The significance of the Siege of Vicksburg in the Civil War was immense, as it marked a turning point for the Union forces. The siege lasted from May 18 to July 4, 1863, and resulted in the capture of the city by Union General Ulysses S. Grant. This victory gave the Union complete control over the Mississippi River, effectively splitting the Confederacy in two and cutting off vital supply lines. The siege demonstrated the effectiveness of siege warfare and boosted Union morale while simultaneously diminishing Confederate resources and strategic capability, altering the course of the Civil War.