Historians have examined the tactical aspects of the Vicksburg campaign in great detail. Since hundreds of articles have already been written on the tactical conduct of the campaign, not much new information can be added to the body of knowledge that already exists. What is lacking in the analysis of the Vicksburg campaign is how it was logistically supported. This thesis analyzes how General Ulysses S. Grant supported the Army of the Tennessee during the campaign. This thesis also reviews the supply organization of the North, since it was this structure that kept Grant's army provisioned for nearly five months in Confederate territory. The conclusion of this thesis differs from the widely held belief that Grant cut loose from his base of supplies right after he landed on the east bank of the Mississippi River. This thesis concludes that Grant was supplied throughout the campaign from supplies drawn from his bases at Milliken's Bend, Young's Point, and Grand Gulf. Finally, this thesis provides supply tables for the Army of the Tennessee. These tables are provided for two reasons: first, to show the amount of supplies the Union army is believed to have required; and second, to illustrate the sheer size of the logistics effort of the Vicksburg campaign. No analysis of the campaign is complete without an understanding of this last point.