All through traffic on the Mississippi River was controlled by the Confederate fortress at Vicksburg, Mississippi. Situated atop seemingly insurmountable cliffs, the fort and its big guns determined whose men and supplies flowed down the critical water highway.
So well defended by nature and big guns was the fort that Union General Ulysses S. Grant spent more time trying to figure out how to circumvent the fort than attack it. Several schemes involving canals, dredges, and levees were explored; if a new ditch could be dug, Vicksburg could be avoided and Northern military transports could work their way down Ol’ Muddy. But none of these schemes panned out. Grant had no choice but to take Vicksburg if he were to take the Mississippi. And perhaps where modern technology had failed, ancient military tactics could succeed.
Grant began by marching his army down the western bank of the Mississippi well past Vicksburg located on the eastern bank. To cross the river he had no other choice but to order his transport boats to parallel his movement—that is, float past the fort and its deadly accurate guns. Those ships that made it, ferried Grant and his men to the Vicksburg side of the river about 25 miles south of the fort.
Next, Grant marched 50 miles east to Jackson, the state capital, to establish control over the supplies that might be used to restock Vicksburg. For a time, the Confederate commander at Vicksburg, John C. Pemberton, was confused by Grant’s movements and distracted by some diversionary raids order by Grant and led by Col. Benjamin Grierson. But soon enough, Pemberton figured out what was up –Grant was planning to lay siege to his fortress. Caught in something of a Catch-22—afraid to leave Vicksburg undefended but anxious to support the small army engaged in delaying Grant’s progress, Pemberton sent out a small force to help intercept the Union general. But his desperate gambit failed. Pemberton was forced to retreat to the heavily barricaded city with Grant hot on his heels.
Grant, a hard charger by nature, initially tried take the fort by storm, first on 19 May and then again three days later. But after taking heavy casualties, he settled in for a long siege. His 75,000 men easily contained the 30,000 Pemberton had entrenched within the city-fort. Grant’s troops also proved sufficient to fend off General Joe Johnston’s desperate attempt to break Grant’s stranglehold by attacking from the east.
Without reinforcements and without supplies, Pemberton's army and the civilian population of the city faced terrible hardships. To escape the barrage let loose by Union gunboats hovering outside, locals hid in caves. To fend off starvation, they ate anything they could find—by late June all the army’s mules had been stewed. Yet Grant’s grip was relentless, his siege could not be broken. On 4 July 1863—four score and seven years after the Declaration of Independence was read—and one day after Pickett’s charge sent the Confederacy to a devastating defeat at Gettysburg—Pemberton surrendered Vicksburg to Grant. The North now controlled the Mississippi.