The Siege of Vicksburg was one of the most important Union victories of the American Civil War and a major turning point in the conflict. Lasting 47 days from May 18th to July 4th, 1863, the siege saw Union General Ulysses S. Grant surround and starve out the Confederate garrison defending the city of Vicksburg, Mississippi, on the banks of the Mississippi River. The Confederate surrender on July 4th, 1863, gave the Union control of the entire Mississippi River and effectively split the Confederacy in two, dealing a blow to the Southern war effort from which it never fully recovered.
What Was the American Civil War?
The Siege of Vicksburg took place during the third year of the American Civil War, which was one of the most devastating conflicts in the history of the United States. The Civil War was fought between the Northern states, known as the Union, and the Southern states, known as the Confederacy, from 1861 to 1865. At its heart, the war was driven by the issue of slavery, which had divided the country for decades. By 1863, control of the Mississippi River had become one of the most important strategic goals of the entire war. The Mississippi was the main transportation route through the heart of the continent, and whoever controlled it controlled the movement of supplies, troops, and goods across the entire region. President Abraham Lincoln described Vicksburg as the key to the war, and Confederate President Jefferson Davis called it the nailhead that held the South’s two halves together. Both men understood that the fate of Vicksburg would have enormous consequences for the outcome of the war.
Siege of Vicksburg – Background and the Vicksburg Campaign
Vicksburg was one of the most strategically important cities in the entire Confederacy. Situated on high bluffs overlooking the Mississippi River in Mississippi, it was heavily fortified and extremely difficult to attack directly. The city’s Confederate guns controlled a wide stretch of the river, preventing Union ships from passing freely. Grant had been trying to capture Vicksburg since late 1862, but a series of attempts had all failed. Direct attacks from the north were blocked by swampy terrain and Confederate defenses, and efforts to dig a canal that would divert the river around the city came to nothing.
In the spring of 1863, Grant developed a bold new plan. He would march his army down the west bank of the Mississippi River, well south of Vicksburg, and then use the Union navy under Admiral David D. Porter to ferry his troops across the river to the east bank below the city. This required Porter’s gunboats and transport ships to run past the Confederate batteries at Vicksburg at night, a dangerous operation. On the night of April 16th, 1863, Porter’s fleet successfully ran the batteries under heavy fire, with all ships making it through. A second run on April 22nd brought additional transport ships south. Grant’s army crossed the Mississippi at Bruinsburg, Mississippi, on April 29th and 30th, landing on the east bank without opposition.
Once across the river, Grant moved with remarkable speed. Rather than keeping his army connected to a traditional supply line, he largely lived off the land, moving fast and striking hard before the Confederates could react. Over the next 17 days, Grant won five separate battles, captured Jackson, the capital of Mississippi, on May 14th, 1863, and cut off Vicksburg from any hope of outside reinforcement. The key battle of this campaign was fought at Champion Hill on May 16th, where Grant’s forces defeated Pemberton’s Confederate army in open battle and drove it back into the fortifications of Vicksburg. By May 18th, Grant had Vicksburg surrounded.
Siege of Vicksburg – Failed Assaults
With Pemberton’s approximately 30,000 Confederate soldiers now trapped inside Vicksburg’s defensive lines, Grant initially tried to take the city by direct assault rather than a long siege. On May 19th, Union troops attacked the Confederate fortifications but were repulsed with significant casualties. Unwilling to give Pemberton time to strengthen his defenses further, Grant ordered a second, larger assault on May 22nd. Union artillery bombarded the Confederate works for four hours before three corps of infantry attacked simultaneously along the entire Confederate line. The assault was again beaten back with heavy losses, as the Confederate defenders used the natural terrain and their prepared fortifications to great advantage. After these two failed assaults, Grant accepted that Vicksburg could not be taken by direct attack and settled in for a siege.
Siege of Vicksburg – The Siege
Grant established a tight perimeter around Vicksburg, stretching for miles along the eastern side of the city while Union gunboats controlled the river to the west. His army gradually grew to approximately 77,000 soldiers, far outnumbering Pemberton’s trapped garrison. Grant’s men dug a network of trenches that inched steadily closer to the Confederate defensive lines, slowly tightening the grip on the city. Union artillery and gunboats bombarded Vicksburg continuously, day and night.
Inside the city, conditions became increasingly desperate. Food supplies ran low and then ran out as the weeks passed, with soldiers and civilians alike reduced to eating mules and rats. Many of the city’s civilians were forced to dig caves into the hillsides to shelter from the constant shelling. The city was completely cut off from the outside world. Attempts by Confederate forces elsewhere to organize a relief expedition and break through to Vicksburg came to nothing, as Grant had positioned part of his force to face outward and block any such attempt.
In an effort to break through the Confederate lines, Union engineers dug a tunnel beneath one of the Confederate strongpoints, packed it with approximately 2,200 pounds of black powder, and detonated it on June 25th, 1863. The explosion created a large crater and temporarily opened a gap in the Confederate line. However, the Confederate defenders had anticipated the mining operation and built a second line of defense behind the first. Union troops who rushed into the crater found themselves trapped under fire from three sides and were forced to withdraw after more than 20 hours of fighting. A second mine was exploded on July 1st with similar results. The siege continued.
Siege of Vicksburg – Surrender
By late June, Pemberton’s garrison was near collapse from hunger and exhaustion. On June 28th, Pemberton received an anonymous note from within his own ranks, warning him that his men would soon be unable to fight and urging him to seek terms. Pemberton consulted with his senior officers on July 1st and was told that his men were not physically capable of attempting to break through Grant’s lines. On the morning of July 3rd, 1863, white flags appeared over the Confederate defensive works. Pemberton and Grant met between the lines that afternoon to discuss terms of surrender. Grant initially demanded unconditional surrender, as he had done at Fort Donelson. Pemberton refused. Grant then offered to parole the Confederate soldiers rather than send them to prison camps, an arrangement that would also avoid the logistical challenge of transporting and housing 30,000 prisoners. Pemberton and his generals accepted these terms.
On the morning of July 4th, 1863, approximately 29,000 Confederate soldiers marched out of their defensive lines, stacked their weapons, and surrendered. Along with the soldiers, Grant took possession of 172 Confederate cannons and 50,000 rifles. The Siege of Vicksburg was over.
Siege of Vicksburg – Aftermath
The fall of Vicksburg had enormous consequences for the war. Five days later, on July 9th, the Confederate garrison at Port Hudson, Louisiana, also surrendered to Union forces, giving the Union complete control of the entire length of the Mississippi River. The Confederacy was now split in two, with the states of Texas, Arkansas, and Louisiana cut off from the eastern Confederacy. Supplies, troops, and communication across the river became nearly impossible for the remainder of the war.
The timing of Vicksburg’s fall made its impact even greater. The Confederate surrender came on July 4th, 1863, the day after Lee’s defeat at Gettysburg in Pennsylvania. Together, these two events marked the turning point of the entire Civil War. The Confederacy had lost two major armies and control of the Mississippi River within 24 hours. Lincoln celebrated both victories and later wrote to Grant expressing his gratitude and acknowledging that he had been wrong to doubt Grant’s strategy during the campaign.
For Grant personally, the victory at Vicksburg cemented his reputation as the Union’s most capable commander. He was promoted to Major General in the regular army on the day of the surrender. Within a year, Lincoln would appoint Grant as General in Chief of all Union armies.
Significance of the Siege of Vicksburg
The Siege of Vicksburg stands as one of the most strategically significant events of the American Civil War. The campaign that led to the siege demonstrated Grant’s boldness, speed, and ability to operate without a traditional supply line, qualities that set him apart from most other commanders of the war. The siege itself showed that patient, methodical pressure could achieve results that direct assault could not. Most importantly, the fall of Vicksburg split the Confederacy in two, deprived the South of the Mississippi River as a supply and communication route, and came on the same day as the Confederate defeat at Gettysburg, making July 4th, 1863, arguably the most consequential single day of the entire Civil War.
