Grant attacked Lee relentlessly for seven weeks — taking 55,000 casualties but refusing to retreat — grinding the Confederate army down until it had no choice but to hide behind Petersburg's walls.
The Overland Campaign (May 4 – June 24, 1864) was Grant's direct assault on Lee's Army of Northern Virginia — a brutal seven-week series of battles unlike anything Virginia had seen, driven by Grant's simple but revolutionary strategy: keep moving, keep attacking, never give Lee time to recover.
Every previous Union general who had fought Lee in Virginia had retreated after a bloody repulse. Grant did not. After the Wilderness — a nightmarish battle in dense forest where the woods caught fire and wounded men burned alive — Grant moved his army south rather than back. His soldiers reportedly cheered when they realized they weren't retreating.
At Spotsylvania's 'Bloody Angle' on May 12, soldiers fought hand-to-hand for eighteen continuous hours in pouring rain across a low earthwork, rifles passing back and forth through gaps in the logs, men fighting with bayonets and fists. It was among the most savage close-quarters combat of the entire war.
Grant's costliest decision came at Cold Harbor on June 3, where he ordered a frontal assault on heavily entrenched Confederate positions. The attack was repulsed in minutes with 7,000 Union casualties. Grant later said it was the one assault of his career he wished he could take back.
Confederate losses were roughly 30,000–35,000 — lower than Union casualties of nearly 55,000, but representing a far higher proportion of Lee's smaller army. Crucially, the South could not replace its dead; the North could. Grant was trading losses he could absorb for losses Lee could not.
By late June, Lee was pinned behind the fortifications of Petersburg, exactly where Grant wanted him. The mobile army that had won so many campaigns against superior forces was now trapped in a siege it could not survive. The Overland Campaign had not destroyed Lee's army — but it had made destruction inevitable.