Before the American Civil War the Mississippi river had been the most important commercial artery in the United States, the main route for the trade of the mid-west (then known as the north-west), and for much of the cotton trade. The outbreak of the civil war blocked the Mississippi to northern trade. Opening the river and restoring that trade became one of the main Union objectives during the first half of the war (despite the fact that the new railroads had already replaced the Mississippi as the most important trade route from the north west). Union control of the Mississippi would also serve to cut the Confederacy in half, isolate Texas, Louisiana and Arkansas, as well as cutting the land route to Mexico, an important route for bypassing the Union blockade of the south.
Initial progress had been good. The capture of New Orleans in April 1862 had blocked the Mississippi to southern trade, while the loss of Fort No. 10 threatened Southern control of the rest of the river. By the end of 1862 the only stretch of the river blocked to North ships ran between Vicksburg, Mississippi and Port Hudson, Louisiana. Even that stretch of water was not safe for southern ships, as Union warships from the south were able to slip past the guns of Port Hudson.
Nevertheless, Vicksburg remained a potent barrier on the river. Its guns controlled the river, apparently preventing Union ships getting south of the city. On land the city was protected by geography. The Mississippi had created a wide, wet, swampy valley, but with very clear edges, where higher, drier ground met the swamp. Vicksburg was situated at a point where the Mississippi River touched the eastern edge of its flood plain, with vast swamps to the north guarded by a series of ‘bluffs’ (the steep sides of the valley). The only dry ground was to the south of the city.
The problem facing U. S. Grant, whose job it was to capture Vicksburg, was how to get his army on to that dry ground. An attempt to travel overland to the east of the river had come to grief in December 1862 when his vulnerable supply lines had been broken. Across the rest of the winter of 1862-3 Grant had attempted to find some way to bypass Vicksburg, normally involving some sort of canal building through the Mississippi swamps. Each ended in failure, and by the spring of 1863 Grant’s reputation in the north was in serious danger.
The same was true in Vicksburg. Showing impeccable timing, on 16 April 1863 a gala ball was held in Vicksburg to celebrate the lifting of the Union threat. The dancing was sadly interrupted by the roar of gunfire from the gun batteries on the river. Grant had decided to run his fleet past the guns of Vicksburg, and use the survivors to ferry his army across to the east bank, below the city. By the end of April, 23,000 Union soldiers, soon reinforced to 40,000, were at loose south of Vicksburg.
This was something of a gamble on Grant’s part. If Pemberton’s 30,000 men could be combined with other Confederate forces in the area, then Grant would face an army the size of his own, operating in its home territory. However, in the first half of May Grant launched his most skilful campaign (Big Black River campaign, 7-18 May 1863). Moving north east along the line of the Big Black River, he separated Pemberton from the forces being assembled at Jackson, under the eventual command of General Joseph Johnston. After defeating these forces at Raymond (12 May) and Jackson (14 May), Grant turned east and inflicted two serious defeats on Pemberton’s field army at Champion’s Hill (16 May) and Big Black River (17 May). On 18 May, Pemberton’s army trooped back into Vicksburg having lost over 5,000 men.
The following day (19 May) Grant’s army arrived in front of the defences of Vicksburg. Grant decided to launch an immediate assault on the city. This was probably a good decision, although the attack was repulsed. Pemberton’s men had suffered two serious defeats in the last three days, and at Big Black River had broken and fled without putting up any serious opposition. If they were still that demoralised, then there was a chance that a sudden attack would force a collapse.
Despite their recent defeats, Pemberton’s Confederates were not so demoralised that they could not hold the defences of Vicksburg. The terrain around Vicksburg was ideal for construction of strong defences. Pemberton’s engineers had spent the last seven months constructing those defences. The higher ground around Vicksburg was crossed by a series of streams, each of which had cut a deep, steep sided ravine, leaving a series of ridges. One of these ridges was used by the Confederate engineers. Nine forts, linked by trenches and rifle pits, combined to make the strongest defences seen in the war so far.
Their strength was confirmed by the repulse of a second, more carefully prepared Union attack on 22 May. Only now was Grant ready to settle down for a regular siege. He did not believe that these attacks had been a mistake. He was later to say that his men would not have been as patient in the siege if they had not tried and failed to assault the lines. He was also worried that Johnston was still in his rear, slowly increasing the size of his army (eventually it numbered some 30,000 men). Finally, the threat of disease in a southern summer made it preferable that the siege ended sooner rather than later.
Despite the strength of the defences, Vicksburg only hope was that Johnston, or some other Confederate commander, would come to the relief of the city. However, even now troop shortages were beginning to plague the Confederacy. Braxton Bragg had already sent two divisions west, weakening his army at a key moment. Robert E. Lee had the most available troops, and after Federal reverses at Fredericksburg and Chancellorsville was under no threat of sudden attack. However, Lee was about to invade the north for the second time (the campaign of Gettysburg), and did not want to send troops west. West of the Mississippi there were not enough men to make much of a difference. Still, the commander in Louisiana, General Richard Taylor, at least made the effort, sending three brigades to attack Grant’s supply line. When this expedition was defeated at Milliken’s Bend (7 June 1863), the only hope for the defenders of Vicksburg was that Joseph Johnston would come to their rescue.
He was in no position to do so. He eventually had 30,000 men in his army, but many of them were inexperienced. They were poorly equipped and worst of all had little or no proper transport. As his army got bigger, so did Grant’s, until 70,000 Union men surrounded Vicksburg, with seven divisions under Sherman facing east to deal with any Confederate counterattack.
Grant was not content to wait for hunger to force the surrender of Vicksburg. All across June his men constructed a series of trenches just as elaborate as the Confederate defences of the city, in a classical siege operation. Slowly these trenches crept closer and closer to the defences. Tunnels were dug under the Confederate lines, and mines exploded. The first mine, on 25 June, produced a big crater but little else – the defenders of the city had detected it and build a second line of defence further back, and a Union assault had been repulsed with heavy losses. A second mine, on 1 July, had destroyed a Confederate fort, but had not been followed by an assault. Grant had decided to wait until he could explode a series of mines and use the confusion to launch a general assault along the line. ‘D-Day’ was set for 6 July.
In the end that attack was never needed. Inside Vicksburg food was running desperately low. On 28 June Pemberton had received an anonymous note from amongst his men asking him to surrender before the army deserted. On 1 July Pemberton consulted with his senior officers about the possibility of fighting there way through the Federal lines, and was told that his men were no longer physically capable of making the attempt.
Pemberton pondered his choices for a day, and then on the morning of 3 July white flags appeared on the Confederate defences. Grant and Pemberton met between the lines at 3 o’clock on the same afternoon. That meeting did not go well. Grant insisted on unconditional surrender, Pemberton refused. Later that day, Grant discussed these terms with his corps commanders, and the naval commander, Admiral Porter. After that conference, Grant revised his terms. This time the Confederate soldiers would be allowed to leave Vicksburg having given their parole not to fight again, unless officially exchanged for Northern prisoners. These more generous terms had two main purposes. The first was to reduce the stress on Grant’s supply lines – 30,000 men would have been very difficult to transport north, and at end of their journey would probably have been paroled in Virginia anyway. Second, Grant hoped that 30,000 disaffected ex-soldiers wandering around the Confederacy would do a great deal of damage to morale.
Late at night on 3 July these terms were accepted. The following day, 4 July, was Independence Day. Pemberton was later to claim (unconvincingly) that he had timed the negotiations with that in mind, expecting to get better terms). Whatever the reason for it, the surrender of one of the most important places in the Confederacy on that date was a massive blow to southern morale, and provided a crucial boost to that of the north. 2,166 officers and 27,230 men surrendered at Vicksburg, and within a few weeks were scattering across the south with their tale of defeat.
The surrender of Vicksburg quickly led to the surrender of Port Hudson, now the last Confederate stronghold on the Mississippi. Once the garrison there were sure that Vicksburg had surrendered, they too capitulated (9 July). The Mississippi was now clear for northern ships. Only one week later the first ship reached New Orleans from the north. The Confederacy was permanently split in two. The Mississippi River, once the greatest link in the south, was now a great barrier.
The capture of Vicksburg promoted U.S. Grant to the front rank of Union generals. As the Union armies approaching Chattanooga, away to the north east in Tennessee, began to run into problems, Lincoln turned to Grant. After the great Confederate victory at Chickamauga on 19-20 September 1863, Grant was appointed to command of all Union armies between the Mississippi river and the Alleghany Mountains, and ordered to lift the siege of Chattanooga. He was on his way to supreme command.