This thesis studies the logistics involved in mobilizing and supplying the Union Army at the onset of the Civil War. The main elements discussed are the sources, procedures, and items needed for the mobilization and supply efforts. Initially, the Union relied on the States to mobilize the military with the majority of the military being militia members or volunteers. The number of volunteers declined later in the war and the Union used both the bounty system and the draft for recruitment. Eventually, the Federal Government replaced the States as the primary mobilizing entity. The military needed supplies of weapons, clothing, and food. Again the States were the primary providers of supplies. The Union later used domestic and foreign markets for supplies, but the urgency of the nation spawned fraud and corruption. Additionally, the majority of the supplies provided were not adequate for the environment of war. By the end of war, corruption decreased and quality increased. Today\u27s military can use the actions of the Union as guidance of what to do and what not to do in the time of war. The actions of the Union during the Civil War should be used as a template for future generations