The Port Hudson State Historic Site is located on the Mississippi River north of Baton Rouge in East Feliciana Parish, Louisiana, just outside the limits of Port Hudson and in the vicinity of Jackson. The site preserves a portion of the fortifications and battle area of the longest siege in American history, during the American Civil War from May 23 through July 9, 1863. The state of Louisiana maintains the site, which includes a museum about the siege, artillery displays, redoubts, and interpretive plaques. Historical reenactments are held each year. It was designated a National Historic Landmark in 1974, significant as the first place where African-American military units fought for the Union Army under African-American field leadership.
Port Hudson State Historic Site is located north of the community of Port Hudson, on the west side of United States Route 61. The property of the site extends west to Thompson Creek, and is bounded on the north by Sandy Creek and partly on the south by Foster Creek. This area forms a terrace about 65 to 80 feet (20 to 24 m) above the creeks, with twisting and steep terrain that made for a natural defensive position, and is where Union Army forces were dug in. The area immediately to the southwest of Foster Creek has similar terrain, and is where Confederate defensive positions were located. These positions were but a small portion of the total offensive and defensive positions, which entirely ringed the community, and included artillery emplacements overlooking the nearby Mississippi River.
An addition of 256 acres (1.04 km2) to the site was made possible by The Conservation Fund using its Battlefield Revolving Fund established by grants from The Gilder Foundation and contributions from a number of partners.
The Siege of Port Hudson was part of a concerted Union effort to gain full control of the Mississippi River. It was conducted May 22 – July 9, 1863 by forces under the command of Major General Nathaniel Prentice Banks, and only ended because the Confederate General Franklin Gardner surrendered after learning of the fall of Vicksburg, Mississippi to Union forces. General Banks gave orders to two units composed entirely of African Americans, the 1st and 3rd Louisiana Native Guards, to attack the Confederate positions south of Foster Creek on the morning of May 27. There was in Union military circles some question about how these units would perform, which were among the first to include African-American field commanders. The units acquitted themselves well, reaching to within 50 feet (15 m) of the Confederate batteries three times before being repulsed. The overall attack plan ordered by Banks was a failure, in part due to the piecemeal, disorganized, and uncoordinated execution of its elements. The units that fought against this position suffered 37 killed, 155 wounded, and 116 missing (out of just over 1,000 men deployed), and remained in the field until ordered to retreat at 4:00 PM.