Abraham Lincoln, who had spent time on the Mississippi River in his youth, knew well its strategic value: “See what a lot of land these fellows hold, of which Vicksburg is the key! The war can never be brought to a close until that key is in our pocket” he had said. For the North, the Mississippi was a dagger pointed at the vitals of the Confederacy. Tributary rivers like the Yazoo, Red and Arkansas provided invasion routes into the Confederate interior. Union control of the river would maintain an uninterrupted route to the Gulf of Mexico for northern commercial products and war materiel. As early as 1861, the Union’s chief general, Winfield Scott, proposed controlling the Mississippi as part of his Anaconda Plan.
For the South, the river sliced the Confederacy in two. Access to the west and valuable resources from Texas, Arkansas and Louisiana were inaccessible if the river was lost. Confederate control of the river would deny Northern commerce and stop invading Yankee armies.
The first Federal campaigns focused on the upper river, with victories at Belmont and Island Number 10 in November 1861 and April 1862. Maj. Gen. Ulysses S. Grant won victories at nearby Forts Henry and Donelson on the Tennessee and Cumberland Rivers in February, 1862. In all those battles, the army was assisted by shallow-draft “brown water” U. S. Navy gunboats under Flag Officer Andrew H. Foote. In April 1862, deep-draft ships under Flag Officer David G. Farragut captured New Orleans and ventured up the river all the way to Vicksburg but were turned back. That same month, Grant defeated the Confederate army at Shiloh, and in June Union forces captured Memphis. With victories behind him, Grant focused on the 100-mile stretch of river between Vicksburg and Port Hudson that remained in Rebel control.
Mississippian Jefferson Davis described Vicksburg as “the nailhead that held the two halves of the south together.” Nicknamed the “Gibraltar of the Confederacy,” the town was situated on high bluffs overlooking a 180-degree bend in the river. Surrounding Vicksburg were swamps and bayous that made a cross-country assault nearly impossible. Heavy artillery commanded the water and land approaches to the city, and nearly eight miles of trenches studded with forts, redoubts and redans ringed the town. Command of the defenses fell to Maj. Gen. John C. Pemberton. Born in Philadelphia but married to a Virginian, Pemberton commanded 30,000 troops but had virtually no cavalry. Without troopers, Pemberton knew little of Grant’s whereabouts as his old pre-war friend maneuvered his army toward Vicksburg.
Union hold of the strategic railroad junction at Corinth was finally won in October 1862, giving Grant a free hand to base his Army of the Tennessee around Holly Springs. In December, Grant began a two-pronged advance to Vicksburg. One column under Maj. Gen. William T. Sherman was moved downriver by Navy transports and approached Vicksburg via Chickasaw Bayou north of the city, while Grant advanced southward down the Mississippi Central Railroad. Confederate cavalry under Maj. Gen. Earl Van Dorn plundered Grant’s supply line, forcing him back while Pemberton’s men stopped Sherman on December 29.
Unfazed, Grant conducted a series of “experiments” up, down, and across the bayous and rivers north and west of Vicksburg during the early months of 1863, but found little success reaching the city. Realizing that an assault based on the west bank of the river held the best chance for victory, Grant kept a supply base at Milliken’s Bend and moved south below Vicksburg on the Louisiana side of the river. On the night of April 16, admiral Porter’s gunboat fleet successfully ran south past the Confederate batteries, giving Grant the naval power necessary to force a river crossing. Feinting north of Vicksburg with Union cavalry and Sherman’s force on the Yazoo, Grant sent Porter’s gunboats to reduce the two forts at Grand Gulf, his preferred crossing site, 24 miles south of the city. Porter’s fleet engaged the Confederate guns there on April 29, silencing one fort but not the other. Undaunted, Grant changed his plan and the next day crossed at Bruinsburg, five miles below Grand Gulf.
Grant’s roughly 75,000 men were grouped into three army corps. Sherman commanded the XV Corps which crossed the river at Grand Gulf after the Confederates evacuated it. The XIII Corps under Maj. Gen. John A. McClernand and the XVII Corps led by Maj. Gen. James B. McPherson moved forward with Grant.
Instead of marching directly toward Vicksburg, Grant moved northeast, guiding on the Big Black River on his left, toward the rail center at Jackson, where he intended to cut the Southern Railroad supplying Vicksburg. As Grant advanced, the Confederates gave him battle at Port Gibson on April 30-May 1, Raymond on May 12, Champion Hill on May 16, and at the Big Black River bridge on May 17. Heavy losses dwindled Pemberton’s strength, but stubborn fighting once back inside his defensive works proved that Grant would have a hard time dislodging him.
Gen. Joseph Johnston, sent to Mississippi by Davis to salvage the military situation, had gathered about 6,000 men around Jackson that might have been sent to Pemberton’s aid. Johnston arrived too late and evacuated Jackson after a small battle. Not wishing to occupy the city, Grant ordered everything of military value destroyed. Johnston remained in Mississippi with his force, but made no major effort to relieve Pemberton. While Davis insisted Vicksburg be defended at all costs, Johnston ordered Pemberton to evacuate the town. Choosing to defend the city rather than save his army sealed Pemberton’s fate.
Grant launched major assaults against Pemberton on May 19 and 22 and was repulsed with heavy casualties each time. Undeterred, and with reinforcements sent to him from Helena, Arkansas and Memphis, Grant decided to besiege the city. By mid-June, Union soldiers had dug mines under the Confederate works. Filled with explosives, the first of these was detonated under the 3rd Louisiana Redan on June 25. Thousands of men from both sides filled the crater in hand-to-hand combat with no decisive result. Within two weeks, Grant would be prepared to blow up 13 more mines along Pemberton’s position.
After holding out for 47 days, with no reinforcements and low on food and supplies, Pemberton surrendered on July 4. Nearly 30,000 Confederates were paroled; the second time in the war that Grant had captured an entire Confederate army. Grant's Vicksburg Campaign was one of the most brilliant of the war. In 17 days, his army marched more than 200 miles, winning five battles before confronting Pemberton at Vicksburg. With the loss of Pemberton’s men at Vicksburg and the Union victory at Port Hudson five days later, the Union controlled the entire Mississippi River and the Confederacy was effectively split in half. Abraham Lincoln happily greeted the news of Vicksburg’s surrender: “The father of the waters goes unvexed to the sea,” the President proclaimed.