Union efforts to capture Vicksburg, Mississippi, began in May 1862 with a failed naval strike against Confederate guns along the river. Summer offensives also stalled, and it was not until winter that Ulysses S. Grant took command of the campaign. Engineers then launched an ambitious scheme: dig a canal beside the city to divert the Mississippi River and bypass Vicksburg’s forts entirely.
Military leaders hoped that shifting the river’s course would make the fortified city strategically irrelevant. The work, however, stalled under brutal heat and outbreaks of tropical diseases like malaria and dysentery, which sickened the laborers. In January, Grant restarted the digging under President Lincoln’s close watch, with daily updates sent to the White House. Though Grant privately doubted the canal would work, he saw value in keeping his troops busy and battle-ready for the spring campaign.
From January to March 1863, five more attacks, including a naval move up the Yazoo River, failed to crack Vicksburg’s defenses. Grant later characterized these efforts as reconnaissance that proved the city’s near-total invulnerability. As digging continued into March, river surges broke through the barriers and flooded the unfinished canal. Union engineers brought in steam dredges to clear the channel, but Confederate spotters on the bluffs quickly targeted them with deadly accurate fire.
That final blow ended the hydraulic approach for good. With options fading, Grant made a daring pivot: a full land assault from Vicksburg’s eastern side. To pull off the flanking maneuver, his army needed to slip behind Confederate lines. Troops marched south along the river’s west bank, but crossing required naval support.
Rear Admiral David Porter’s fleet proved critical. On the night of April 16, under heavy Confederate fire, Porter steered his ironclads past Vicksburg’s forts in a risky run. Early attempts to land at Grand Gulf failed, pushing Union forces further downstream to Bruinsburg. The river crossing there on April 30 started Grant’s invasion of Confederate Mississippi.
Grant’s confidence in operating without a fully established supply line came from earlier experience. During previous Vicksburg campaigns, broken supply lines had forced his men to successfully live off the land, scavenging crops and farms. Grant believed his army could temporarily take local food if needed. Contrary to a common myth, Grant never fully cut his supply lines.
His memoirs mention a separation on May 3 that caused confusion, but records show only a 72-hour gap in supplies between the Bruinsburg crossing and the capture of Grand Gulf on May 3. After taking Grand Gulf, Grant set up a clever resupply chain. Wagons packed with ammunition and hardtack used a hidden riverside trail through the floodplain. Critics, including General William Tecumseh Sherman, warned that such a thin route could not feed 50,000 men and urged a pause.
Grant’s reply clarified his plan: combine carried rations with local food to keep the troops moving. Bread and coffee would maintain fighting spirit until full supplies returned. The gamble showcased Grant’s adaptability and ultimately won the campaign. Although Vicksburg was the ultimate prize, Grant stayed disciplined about his immediate targets.
His first Mississippi objective became Port Gibson, because it controlled the roads linking Grand Gulf to Jackson. Seizing that hub would give the Union command of the Southern Railroad, Vicksburg’s vital supply artery. After losing Grand Gulf, Confederate General John Bowen guessed Grant would cross the river and correctly predicted Port Gibson as the target. Grant, meanwhile, sent Colonel Benjamin Grierson on a cavalry raid deep into enemy territory to misdirect the Confederates.
Desperate Confederate calls for backup reached General John Pemberton, who followed his orders to protect Vicksburg above all else and declined to send help. After crossing the river, Union forces split to surround Port Gibson’s two main roads, stretching the thin Confederate defenses. Fighting erupted before dawn on May 1, when Union scouts met hidden Confederate troops near Magnolia Church’s thickets. Pemberton’s delay in sending aid proved catastrophic.
Despite fierce resistance, the outnumbered Southern troops took heavy losses and retreated. Bowen later lamented that his men fought bravely but were overwhelmed. The retreat trapped hundreds of Confederates as prisoners and forced the evacuation of Fort Coburn, handing the outskirts of Grand Gulf to the Union. Losing Port Gibson broke Vicksburg’s outer shield and opened a clear path to the city.
Grant knew that taking Vicksburg meant first stopping Confederate reinforcements. After Port Gibson, he avoided a direct charge on the city and instead worked to destroy its supply networks. His eastern flank plan relied on cutting enemy logistics before delivering the final blow. Intelligence showed that Confederate General Joseph Johnston had reached Jackson with troops meant for Vicksburg, raising the urgency.
Grant immediately saw Johnston’s force as the main threat. Luck struck when Johnston, wrongly believing Vicksburg could not be held, pulled his men back to Canton, leaving Jackson exposed. On May 14, Grant’s army took Mississippi’s capital, destroying war factories and rail lines to keep them out of Confederate hands. Union spies later intercepted Johnston’s orders telling Pemberton to march toward Clinton.
Though Grant knew Johnston’s real position, he sped up operations to prevent the Confederate armies from uniting. Historians believe Johnston’s plan was to sacrifice Vicksburg in order to lure Union forces into kill zones. Pemberton, however, stayed focused on defending the city, expecting reinforcements before a siege. Both commanders miscalculated.
Johnston’s trap failed and Pemberton’s help never came, leaving Vicksburg isolated. With no rescue possible and starvation setting in, Confederate leaders negotiated a surrender. At first, they refused Grant’s call for unconditional surrender. Grant then offered parole, allowing defenders to go home if they vowed not to fight again until they were formally exchanged.
The offer was practical: Grant lacked the supplies to hold thousands of prisoners. Facing doom, the Confederate commanders accepted the terms on July 4, 1863. The surrender gave the Union total control of the Mississippi River, splitting the Confederacy in two.
The victory hastened the South’s collapse and cleared the path to Union victory two years later.