Also called the Battle of Chaffin's Farm. On the night of September 20–29, General Butler and his Army of the James cross the James River to attack the outer defenses of Richmond. At dawn, his columns attacked the Confederates. Fort Harrison was the key to General Butler's plan. It was the strongest point in the Confederate line north of the James. On high ground, the fort had a view all the way to the James River. The fort was lightly held by only 200 Confederate troops as most were in Petersburg at the time. The fort's cannon were old and not considered battle worthy by the Northern artillerymen. The Union attack came unexpectedly and so quickly that there were few Union casualties. The Union Army was successful at both New Market Heights and at Fort Harrison. The Confederates then fought to contain the breakthrough. As Grant predicted, Lee weakened his Petersburg defenses to reinforce his lines north of the James River. Lee counterattacked on September 30 but his efforts were unsuccessful. The Union troops dug in forming trenches around the territory they just captured. The confederates built a new line of defenses that cut off the area captured by the Federal troops. The total casualties were 4,430 including Union General Hiram Burnham. The fort was renamed Fort Burnham in his honor.