Prelude to the Battle
At the onset of the American Civil War, the State of Tennessee comprised most of the northern border of the Confederate States of America in the West. Defending that border was difficult for the Confederacy because three major rivers (the Mississippi, which flows south to the Gulf of Mexico, and the Tennessee and Cumberland Rivers, which flow north to the Ohio River) provided relatively easy access to the South.
Grant Captures Fort Henry and Fort Donelson
By late 1861, President Abraham Lincoln was pressuring Union commanders in the west to invade the South. On January 30, 1862, the Western Theater commander, General Henry Halleck, reluctantly approved Brigadier General Ulysses S. Grant’s request to attack Fort Henry, on the Tennessee River. Within six weeks, Grant captured Fort Henry and Fort Donelson on the Cumberland River, establishing federal control of both waterways.
Federals Focus on the Mississippi River
With two of the three main rivers connecting the North and South under Union control, the Federals turned their attention to the Mississippi River. If Union forces could gain control of the Mississippi, they could deny the Confederacy easy access to supplies from the Gulf of Mexico and territories in the American West.
Admiral David Farragut captured the port city of New Orleans on May 18, 1862, closing down Confederate access to the Gulf. In June, the Union tightened its grip on the Mississippi, when federal forces captured the river city of Memphis, Tennessee. Nevertheless, the South still controlled traffic on much of the river because of its strong fortifications at Vicksburg, Mississippi.
The Gibraltar of the Confederacy
Vicksburg sits on a high bluff on the eastern side of the Mississippi River, south of the mouth of the Yazoo River. Known as “The Gibraltar of the Confederacy,” the city seemed to be impregnable. The high bluff upon which the city sits made it nearly impossible to assault from the river. Farragut made two attempts to do so in May and June 1862, but both excursions failed. To the north, nearly impenetrable swamps and bayous protected Vicksburg. To the east, a ring of forts, mounting 172 guns, shielded the city from an overland assault. The land on the Louisiana side of the river, opposite Vicksburg, was rough, etched with poor roads and many streams.
Grant Tries to Capture Vicksburg
In July 1862, President Abraham Lincoln summoned Major General Henry W. Halleck to Washington to serve as chief of all Union armies. Halleck’s departure left Major General Ulysses S. Grant in charge of operations in the Western Theater.
In December, Grant launched his first attempt to capture Vicksburg. He sent three divisions, commanded by his most trusted subordinate, General William T. Sherman, down the river from Memphis to attack Vicksburg from the north. Meanwhile, Grant approached the city with the bulk of his army from the east, but Rebel cavalry cut his supply lines, forcing him to retreat before launching an assault. Unaware that Grant had pulled back, Sherman attacked, but Rebels forces defeated him at the Battle of Chickasaw Bayou (December 26–29, 1862).
Grant Switches Tactics
During the winter, Grant made several unsuccessful attempts to approach Vicksburg from other directions. When spring arrived, he set a new plan into motion. On March 29, 1863, Grant put part of his army to work erecting bridges, draining bayous, and constructing a road past Vicksburg on the west side of the Mississippi. By mid-April, his men had carved a path through the Louisiana wilderness that would enable Grant to march the Army of the Tennessee past Vicksburg, cross the river, and then attack the city from the south.
Porter Runs the Gauntlet
To complete the river crossing, however, Grant needed the help of his naval forces. On the night of April 16, seven gunboats and three supply ships under the command of Rear Admiral David Dixon Porter ran the gauntlet of Confederate batteries along the river. Despite heavy Rebel fire, Porter passed the city, losing only one ship. On April 22, six more boats made it through, bringing Grant the supplies he needed to launch his assault on Vicksburg.
To divert attention from his main operations, Grant ordered Sherman to feign an attack against Confederate forces stationed at Snyder’s Bluff, upriver from Vicksburg, from April 29 through May 1. Grant also ordered Colonel Benjamin Garrison to stage a daring cavalry raid through central Mississippi, which forced Confederate Commander of the Army of Mississippi, John C. Pemberton, to divert troops away from Vicksburg.
April 29, 1863 — Battle of Grand Gulf
On April 29, 1863, Grant put his grand scheme into action. With the aid of Admiral Porter’s gunboats, Grant attempted to move Major General John A. McClernand’s 13th Army Corps down the Mississippi River on transport barges and execute a landing on the east bank at Grand Gulf, at the juncture of the Mississippi and the Big Black River roughly thirty miles below Vicksburg. Five-and-one-half hours of shelling by Porter’s squadron failed to silence Fort Cobun, a Confederate artillery stronghold guarding the Mississippi River. Grant then called an end to the Battle of Grand Gulf. The Confederate victory proved inconsequential, however.
Grant Bypasses Grand Gulf
Later that night, Grant ordered McClernand and Major General James B. McPherson to march their 13th and 17th Army Corps down the Louisiana side of the Mississippi past Grand Gulf. Meanwhile, Grant’s troop barges, protected by Porter’s gunboats, ran past Fort Cobun. McClernand and McPherson then rendezvoused with Porter at Bruinsburg, fewer than ten miles downriver from Grand Gulf.
Grant Crosses the Mississippi River
The federal soldiers clambered aboard the barges at Disharoon’s plantation on the Louisiana side of the river, crossed over, and disembarked at Bruinsburg on the Mississippi side. The invasion of Mississippi by roughly 23,000 Union soldiers on April 30, 1863, was the largest amphibious offensive in American history prior to the invasion of Normandy, France, during World War II.
Pemberton Remains in Vicksburg
Despite the thousands of Yankees involved, the Confederate forces in the area still outnumbered them. Lieutenant General John C. Pemberton, commander of Confederate troops near Vicksburg, had roughly 30,000 soldiers under his authority. Fortunately for Grant, Pemberton took his orders to defend Vicksburg at all costs literally. Rather than moving forward to confront the Union invasion force at Bruinsburg, where it was most vulnerable, Pemberton kept most of his troops in garrison at Vicksburg. As a result, the landing was unchallenged and the only Confederates nearby were Major General John S. Bowen’s force of 6,000-8,000 soldiers who had marched to Port Gibson after thwarting Grant’s landing at Grand Gulf the previous day.
April 30, 1863 — Federals March toward Port Gibson
As the Union forces came ashore, they secured a beachhead and began marching toward Port Gibson by late afternoon on April 30. The Federals divided their forces and moved along two roughly parallel roads that converged near their objective, about ten miles to the east. McPherson’s Corps marched along Bruinsburg Road. A few miles to the south, McClernand’s Corps traveled along Rodney Road.
Bowen Divides His Forces
Forced to defend two approaches to Port Gibson, Bowen divided his already heavily outnumbered forces. Bowen deployed Brigadier General Martin E. Green’s Brigade west of Port Gibson along Rodney Road and he stationed Brigadier General Edward D. Tracy’s brigade across Bruinsburg Road.
May 1, 1863 — Clash at Port Gibson
As McPherson’s troops moved along Rodney Road in the dark, they encountered light opposition from Green’s advance patrols until stopping at about 3 a.m. The action intensified on both roads at dawn as the Federals resumed their push toward Port Gibson. At roughly 8 a.m., a Union musket ball pierced General Tracy’s breast, killing him instantly, but his men held on until about 10 a.m. when their lines crumbled.
When Confederate reinforcements arrived from Brigadier General William E. Baldwin’s and Colonel Francis M. Cockrell’s brigades, the Rebels established a succession of new lines while being forced back steadily. As the situation deteriorated, Bowen wired his superiors: “We have been engaged in a furious battle ever since daylight; losses very heavy. The men act nobly, but the odds are overpowering.” After two desperate Rebel counterattacks failed in the late afternoon, Bowen recognized the futility of further resistance against the Union onslaught and ordered a retreat, leaving behind several hundred prisoners.
Aftermath of the Battle
The Union victory at the Battle of Port Gibson cost Grant 875 casualties (131 killed, 719 wounded, and 25 missing). Bowen lost 787 soldiers (60 killed, 340 wounded, and 387 missing). Under threat of being surrounded, Bowen also evacuated the formidable Fort Cobun at Grand Gulf, yielding control of the area to Grant’s Army of the Tennessee.
In the battle’s aftermath, Grant turned his army east and drove General Joseph E. Johnston’s forces away from the state capital at Jackson, Mississippi, on May 14, 1863. Johnston’s removal prevented him from uniting his forces with Pemberton, now isolated at Vicksburg. Grant then returned his attention to Vicksburg. Resounding Union victories at the Battle of Champion Hill (May 16) and the Battle of Big Black River Bridge (May 17), forced Pemberton to take refuge within the City of Vicksburg proper. After a prolonged siege, Grant eventually forced Pemberton to surrender on July 4, 1863.