(186465) Series of military operations in southern Virginia at the end of the American Civil War .
The rail centre of Petersburg, Va., was a strategic defense point near the Confederate capital of Richmond. In June 1864 the Union army began a siege of both cities, and each side built fortifications 35 mi (56 km) long. Confederate troops under Robert E. Lee held the cities, but supplies were scarce and Lee's 50,000 troops were immobilized by lack of horses. In April 1865 the 120,000 Union troops under Ulysses S. Grant drove the Confederates behind Petersburg's inner defenses, forcing the evacuation of both cities. Soon thereafter the Confederates surrendered at Appomattox Court House .