The Battle of Forts Jackson and St. Philip (April 18–28, 1862) in the American Civil War was the decisive battle for possession of New Orleans. The two Confederate forts on the Mississippi River south of the city were attacked by a Union Navy fleet. As long as the forts could keep the Federal forces from moving on the city, it was safe, but if they were negated, there were no fall-back positions to impede the enemy advance.
New Orleans, the largest city in the Confederacy, was already under threat of attack from the north when Farragut moved his fleet into the river from the south. Although the menace from upriver was geographically more remote than that from the Gulf of Mexico, a series of losses in Kentucky and Tennessee had forced the War and Navy Departments in Richmond to strip the region of much of its defenses. Men and equipment had been withdrawn from the local defenses, so that by mid-April almost nothing remained to the south except the two forts and an assortment of gunboats of questionable worth. Without reducing the pressure from the north, (Union) President Abraham Lincoln set in motion a combined Army-Navy operation to attack from the south. The Union Army offered 18,000 soldiers, led by the political general Benjamin F. Butler. The Navy contributed a large fraction of its West Gulf Blockading Squadron, which was commanded by Flag Officer David G. Farragut. The squadron was augmented by a semi-autonomous flotilla of mortar rafts and their support vessels under Commander David Dixon Porter.
The expedition assembled at Ship Island in the Gulf. Once they were ready, the naval contingent moved its ships into the river, an operation that was completed on April 14. They were then moved into position near the forts, and on April 18 the mortars opened the battle.
The ensuing battle can be divided into two parts: a mostly ineffective bombardment of the Confederate-held forts by the raft-mounted mortars, and the successful passage of the forts by...