The last Confederate fortress on the Mississippi held out 48 days — finally surrendering only after hearing that Vicksburg had fallen and their cause on the river was lost.
Port Hudson, Louisiana was the last Confederate stronghold blocking Union control of the Mississippi River. Perched on bluffs above the river 25 miles north of Baton Rouge, it was garrisoned by just 7,500 Confederate troops holding off an eventual Union force of 30,000–40,000 for 48 days.
Banks launched two major frontal assaults — on May 27 and June 14 — both of which were repulsed with heavy Union casualties. The June 14 assault alone cost the Union 1,792 casualties against only 47 Confederate, a ratio that illustrated just how futile charging fortified positions had become by 1863.
Among the Union troops at Port Hudson were the Louisiana Native Guards — free Black men from New Orleans who were among the first African American soldiers to engage in combat for the Union. Their assault on May 27 was noted by Northern newspapers, building on the momentum toward full Black military service.
The siege dragged on through the Louisiana summer heat, with disease killing more men than Confederate bullets. Union engineers dug saps and approach trenches, detonated mines, and bombarded the garrison continuously — slowly squeezing a force that was running out of food and ammunition.
When news arrived on July 4 that Vicksburg had surrendered, Confederate commander Gardner's situation became hopeless. There was no relief coming, no possibility of holding indefinitely, and no strategic purpose in prolonging the suffering. He surrendered on July 9, 1863.
Port Hudson's fall completed Union control of the entire Mississippi River, fulfilling Lincoln's strategic vision. 'The Father of Waters,' he said, 'again goes unvexed to the sea.' The Confederacy was now physically cut in two, its trans-Mississippi forces isolated from Virginia and the East.