After their hard-fought victory at the battle of Chancellorsville, Robert E. Lee led his troops northward, through Maryland and into Pennsylvania. The battered Army of the Potomac followed. On July 1 the two armies clashed near the small town of Gettysburg. The Army of the Potomac had a new and untried commander in Gen. George G. Meade. Three days before the battle, Gen. Joe Hooker had resigned his command in a dispute with Lincoln. The early fighting favored the Rebels, who drove the bluecoats back through the town to the high ground south of it.

While Lee uncharacteristically hesitated, the Federals had time to concentrate troops and secure their position on Cemetery Ridge. Late in the afternoon of July 2, the Confederates struck hard against the Union left, leaving thousands dead in wheat field and peach orchard and a maze of rocks known as Devil’s Den. But in the end the Union ranks held. The next day, in a last, desperate bid, forty-two gray regiments started toward Cemetery Ridge in the doomed and gallant charge that will forever bear the name of one of the generals who led it, George Pickett. Although artillery pounded the attackers, inflicting appalling losses, the Rebels pushed forward until they reached the Union line. But they couldn’t hold; in the end five thousand men managed to get back to the place where fifteen thousand had started out not long before.

The Army of Northern Virginia was finished as a fighting force. Lee retreated on July 4. Meade was reluctant to pursue. “We had them within our grasp,” said a frustrated President Lincoln. “We had only to stretch forth our hands and they were ours. And nothing I could say or do could make the Army move.”

But the North was nearly as shaken by victory as the South was by defeat; the three days’ fighting had cost Meade some twenty-three thousand casualties—over a quarter of his force. All told, more than fifty thousand men were killed, wounded, or captured at Gettysburg.

By the time Meade’s army was ready to go back on the offensive, the Army of Northern Virginia had retreated to the other side of the Potomac River, ending the last Confederate offensive in the North.

Less dramatic than Gettysburg, and far less bloody, Gen. Ulysses Grant’s siege of Vicksburg, Mississippi, played an equally crucial role in turning the tide against the South. Grant and his army held the strategically vital city in a choke hold. As one Confederate soldier put it, “A cat could not have crept out of Vicksburg without being discovered.”

Gen. John Pemberton and his thirty thousand Rebel soldiers held out for two months, but when supplies dwindled to nothing, there was little choice. On July 3, as Pickett and his men charged up Cemetery Ridge, Pemberton was discussing terms with his besiegers. He surrendered the city the next day.