Battle of Chattanooga, (November 23–25, 1863), in theAmerican Civil War, adecisive engagement fought atChattanooga on theTennessee River in late November 1863, which contributed significantly to victory for the North. Chattanooga had strategic importance as a vital railroad junction for theConfederacy. In September 1863 a Federal army led by GeneralWilliam S. Rosecrans was besieged there by a Southern army commanded by GeneralBraxton Bragg. The following month GeneralUlysses S. Grant took over the campaign to relieve the Union troops and seize the offensive. With the help of reinforcements from GeneralJoseph Hooker and GeneralWilliam Tecumseh Sherman, the Federal forces defeated the Confederates in the Battles ofLookout Mountain (seephotograph) andMissionary Ridge and lifted the siege; by the end of the month theConfederate army was in retreat into Georgia. Losses of men were less than at Chickamauga (about 6,000 Union and 7,000 Confederate), but the result was completely decisive, ranking in importance withVicksburg and Gettysburg the same year. The way had been opened for Sherman’s march to Atlanta and Savannah the following year.