Why Before Grant could capture Richmond he first had to defeat Confederate forces in?

Before Grant could capture Richmond, he first had to defeat Confederate forces in Petersburg, Virginia. Petersburg was a crucial supply center for the Confederate Army, and its fall would significantly weaken their defenses. By securing Petersburg, Grant aimed to cut off supplies to Richmond, making it easier to launch an assault on the Confederate capital itself. This strategic approach was essential for the Union to gain a decisive advantage in the Civil War.