This thesis examines the interaction between the Union Prison System led by William Hoffman and the Confederate prisoners-of-war, specifically those held at Elmira, New York. By focusing on Hoffman's actions and decisions in the last year of the war, the Confederate death toll can be better understood. The treatise relies heavily on The War Of The Rebellion: A Compilation Of The Official Records Of The Union And Confederate Armies. Two studies were indispensable for this study: Hesseltine's Civil War Prisons: A Study In War Psychology, and Leslie's Hunter's Ph.D. Disseration, Warden For The Union: William Hoffman (1807-1884). The conclusions of my research are: (A) William Hoffman developed a change in actions in 1864, and (B) these actions continued in the last year of the war. As a result of his actions and other factors, Elmira had the highest percentage of death of any Union prison camp. Hoffman's actions led to a higher death rate of Confederate prisoners than has been previously recognized.