The site was selected partially due to its proximity to the Erie Railway and the Northern Central Railway, which criss-crossed in the midst of the city, making it a prime location for a Union Army training and muster point early in the Civil War. Most of the Union installation, known as Camp Rathbun, fell into disuse as the war progressed, but the camp's "Barracks #3" were converted into a military prison in the summer of 1864. The prison camp, in use from July 6, 1864, until the autumn of 1865, was dubbed "Hellmira" by its inmates. Towner's history of 1892 and maps from the period indicate the camp occupied an area running about west and approximately the same distance south of a location a couple of hundred feet west of Hoffman Street and about 35 feet south of Water Street, bordered on