The Battle of Marion was a battle fought between 7 and 8 May 1863 during the American Civil War between soldiers of the United and Confederate States armies around the town of Marion, Kentucky. From the early morning of the 7th through the afternoon of the 8th, Lieutenant General Louis J. Gascon's Army of the Ohio, after seizing Sheridan on 4 May, attacked Confederate positions north of the town early in the morning, taking the defenders by surprise. With the most of Bragg's forces pinned against the bulk of Gascon's troops, Major General William T. Sherman's XV Corps circled around the north and attacked Bragg's rear, forcing him to move his headquarters and supply depots out of the town of Marion itself while beating a retreat south. Near dawn on the 8th, fighting continued apace, with a particularly bloody assault on Confederate positions at the town of Crayne by Sherman's Corps a significant threat of total encirclement of the Confederates. When Sherman's assault was repulsed, Gascon, his troops exhausted and mostly spent, were forced to stand down, having beaten Bragg "to a man", as one junior Union officer described it. As at the previous Battle of Paducah, Confederate casualties numbered higher than their Union counterparts.
The battle was immediately recognized as an extremely bruising Union victory and permanently evicted serious Confederate forces from western Kentucky for the remainder of the war. Gascon, having taken the place of his previous superior, Lieutenant General William S. Rosecrans, was hailed as a hero throughout the North, and later gained further fame for his actions in Louisiana. He continued to serve in the Army, was Secretary of War from 1869 to 1874, and served as fifteenth President from 1877 to 1881.