On June 18, 1864, at the Battle of Petersburg, Ulysses S. Grant ended four days of assaults and began a nine month siege. An excerpt from the article:
"Fact #3: The Petersburg Campaign encompassed 292 days of combat, maneuver, and trench warfare between June 15, 1864, and April 2, 1865.
From June 15-17, 1864, the outnumbered Confederate General Beauregard and his troops saved Petersburg from Union capture. He created a third defensive line along high ground closer to the city and occupied it on the morning of June 18, welcoming reinforcements from Lee’s Army of Northern Virginia. The appearance of Lee’s men ended Federals’ hopes to take Petersburg by storm and ensured a lengthy siege and seemingly endless fighting. For the next nine months, Grant focused on severing Petersburg’s many wagon and rail connections to the south and west. Four offensives between June and October made incremental gains. By the end of the 1864 campaign season, Lee could rely on only a makeshift supply line via the Boydton Plank Road and the South Side Railroad to maintain communications with the south."