Answer: Although Union troops greatly outnumbered Confederate troops, it took months for the North to achieve victory.
Step-by-step explanation:
Petersburg was a very important city to the Confederacy as it supplied both the Confederate General, Robert E. Lee as well as the Confederate capital of Richmond. Capturing it was therefore essentially if the Union were to win the war.
The campaign lasted 9 months and saw huge Union losses which they made up for by greatly outnumbering their opponents. This siege saw extensive trench warfare and eventually ended when General Lee had to abandon the city.