History: American Civil War (1861-1865)

The Mississippi was opened to Union traffic to the southern border of Tennessee with the taking of Island No. 10 and New Madrid, Missouri, and then Memphis, Tennessee. In April 1862, the Union Navy captured New Orleans without a major fight, which allowed Union forces to begin moving up the Mississippi. Only the fortress city of Vicksburg, Mississippi, prevented Union control of the entire river.
General Braxton Bragg's second Confederate invasion of Kentucky ended with a meaningless victory over Maj. Gen. Don Carlos Buell at the Battle of Perryville, although Bragg was forced to end his attempt at invading Kentucky and retreat due to lack of support for the Confederacy in that state. Bragg was narrowly defeated by Maj. Gen. William Rosecrans at the Battle of Stones River in Tennessee.
The one clear Confederate victory in the West was the Battle of Chickamauga. Bragg, reinforced by Lt. Gen. James Longstreet's corps (from Lee's army in the east), defeated Rosecrans, despite the heroic defensive stand of Maj. Gen. George Henry Thomas. Rosecrans retreated to Chattanooga, which Bragg then besieged.
The Union's key strategist and tactician in the West was Ulysses S. Grant, who won victories at Forts Henry and Donelson (by which the Union seized control of the Tennessee and Cumberland Rivers); the Battle of Shiloh; and the Battle of Vicksburg, which cemented Union control of the Mississippi River and is considered one of the turning points of the war. Grant marched to the relief of Rosecrans and defeated Bragg at the Third Battle of Chattanooga, driving Confederate forces out of Tennessee and opening a route to Atlanta and the heart of the Confederacy.