The Richmond–Petersburg Campaign was a series of battles around Petersburg, Virginia, fought from June 9, 1864, to March 25, 1865. Fought during the American Civil War, it is more popularly known as the Siege of Petersburg. But it was not a classic military siege, in which a city is usually surrounded and all supply lines are cut off. Nor was it strictly limited to actions against Petersburg. The campaign consisted of nine months of trench warfare in which Union forces commanded by Lieutenant General Ulysses S. Grant assaulted Petersburg unsuccessfully. Then the Union Army constructed trench lines that eventually extended over . They ran from the eastern outskirts of Richmond, Virginia, to around the eastern and southern outskirts of Petersburg. Petersburg was critical to the supply of Confederate Lieutenant General Robert E. Lee's army and the Confederate capital of Richmond. Numerous raids were conducted and battles fought in attempts to cut off the railroad supply lines through Petersburg to Richmond. Many of these caused the lengthening of the trench lines, overloading dwindling Confederate resources.