The Railroad Redoubt (a/k/a "Fort Beauregard" in post-War accounts) was one of several redoubts, or small defensive earthworks, that were constructed during the American Civil War to protect the city of Vicksburg, Mississippi, from Union attack. It was so named because it was constructed along a major east-west railroad track into Vicksburg. On May 22, 1863, the Union XIII Corps, under the command of Major General John A. McClernand, attacked this portion of the Vicksburg defenses at 10:00 a.m. Within the hour, several units were fighting in or near the ditch fronting the position.