In the spring of 1862, the Union looked toward New Orleans, the largest city in the Confederacy. Military actions in other regions had left the city lightly defended. Its greatest protection from Union invasion came from Fort Jackson and Fort St. Philip, which guarded the water approach seventy-five miles downriver. Both forts were heavily fortified and armed with large cannons; a barricade of sunken ships in the river itself forced approaching craft to stop directly in front of their line of fire. Such a defense seemed insurmountable, and Confederate leaders were confident the two forts could hold off any naval assault the Union might attempt.

But Union military leaders thought otherwise. Naval commander David Porter believed a strong mortar attack from boats on the river could disable the forts' firepower and allow a fleet to pass all the way to New Orleans, and such an attack was readied in early 1862.

To facilitate the invasion, Union general Benjamin Butler captured Ship Island, near the mouth of the Mississippi. The Union's ships were renovated to make them lighter so that they could pass over the river's many sandbars, and the fleet began its long trip up the Mississippi in April, supported by Butler's 15,000 troops for a possible land invasion.

Attacking the Forts

On April 18, Porter began a six-day mortar attack. His nineteen mortar ships lobbed more than 3,000 shells at the forts each day, but they did little damage to the forts' defenses. The bombardment did act as a distraction, and on the night of April 20, two Union gunboats approached the river barricade and cleared a small path for the rest of the fleet.

Squadron captain David Farragut ordered his fleet to proceed, hopeful that enough ships would survive to invade the city of New Orleans. The fleet began the treacherous run under cover of darkness early on the morning of April 24 and was quickly met with cannon fire, which they returned. Confederate officers tried to halt the invasion by sending out a small fleet of wooden ships to ram the approaching Union vessels. Several rafts that had been set on fire were deployed in an attempt to slow the advance.

Farragut's flagship was damaged during the attack, but its crew quickly brought it back into the fray as the Union fleet sank or disabled most of the Confederate ships. All but four of Farragut's fleet made it safely past the supposedly impassable Confederate forts.

Farragut sailed into New Orleans on April 25 and captured the city with little resistance, though the mayor of the city refused to officially surrender. The soldiers manning Forts Jackson and St. Philip laid down their guns on April 28, and Butler and his troops arrived the next day.

Farragut's bold attack on New Orleans placed the city and its port under Union command, a striking defeat for the Confederacy. By taking New Orleans, located 100 miles above the mouth of the Mississippi River, the Union effectively controlled the very gateway to the Deep South.