Port Hudson was the site of the longest siege in American history, lasting 48 days in 1863. During that time, 7,500 Confederate soldiers fought against a force that grew to 40,000 men. The siege was a battle for control of this section of the Mississippi River. Confederate defenders had several advantages despite their smaller numbers, as they had built a series of trenches and earthworks the previous year. After 48 days of siege warfare, the Confederate defenders learned that the Union had successfully captured the much larger Confederate position at Vicksburg. Recognizing that they were the only remaining Confederate defenders of the Mississippi River, and realizing that the Union would be able to send even more soldiers against their own position, the Confederate defenders surrendered Port Hudson on July 9, 1863.
In 1863, Union Major General Nathaniel P. Banks decided to move against Port Hudson. Banks intended to use three divisions to attack from the north while two others advanced from Baton Rouge and New Orleans. By May 22, 30,000 Union soldiers had isolated 7,500 Confederate soldiers behind 4 ½ miles of earthen fortifications. On May 26, Banks ordered a simultaneous attack all along the Confederate perimeter the following morning.
The first Union assault fell on the left wing of the Confederate perimeter. But timely reinforcements allowed for the Confederates to repel the Union attack. In fact the attack was repelled before any other part of the perimeter could be assailed. This resulted in the deaths of over 2,000 Union soldiers including 600 African-Americans of the First and Third Louisiana Native Guard. The guard was led by Captain Andre Cailloux, a black officer. Cailloux was shot while yelling orders in both English and French.
On June 13th another attempt to take the fort was made, which resulted in 1,805 Union casualties, while the Confederates lost less than 200. It took the surrender of Vicksburg to finally force the surrender of Port Hudson. Without it's upriver counterpart, Port Hudson became insignificant, and the Confederate soldiers surrendered on July 9th, 1863. Today, the Port Hudson State Commemorative Area encompasses 889 acres of the northern portion of the battlefield, and has three observation towers, six miles of trails, a museum, a picnic area and restrooms. Four thousand Civil War veterans are buried at the Port Hudson National Cemetery, which stands just outside the old Confederate lines.