Unbeknownst to the Confederates, on July 27, 1864 the Union forces around Petersburg were putting the finishing touches on a huge mine under a fort in the Confederate defenses known as Elliot’s Salient. To divert Confederate attention from this sector of the line, Grant ordered Hancock and Sheridan to cross the James River at Deep Bottom and make a lunge towards Richmond. Grant assumed this would cause a weakening in the Confederate defenses around Petersburg and he was correct in that assumption. Lee in response to Grant’s move pulled some 16,500 men out of the Petersburg lines and into the Richmond fortifications.
In fighting on the 27th and 28th which resulted in 488 Union casualties to 679 Confederate, Hancock and Sheridan’s drive toward Richmond was stopped, but Grant had achieved his goal of drawing Lee’s men to the north side of the James, as Grant noted in his Memoirs:
I concluded, then, a few days later, to do something in the way of offensive movement myself, having in view something of the same object that Lee had had. Wright’s and Emory’s corps were in Washington, and with this reduction of my force Lee might very readily have spared some troops from the defences to send West. I had other objects in view, however, besides keeping Lee where he was. The mine was constructed and ready to be exploded, and I wanted to take that occasion to carry Petersburg if I could. It was the object, therefore, to get as many of Lee’s troops away from the south side of the James River as possible. Accordingly, on the 26th, we commenced a movement with Hancock’s corps and Sheridan’s cavalry to the north side by the way of Deep Bottom, where Butler had a pontoon bridge laid. The plan, in the main, was to let the cavalry cut loose and, joining with Kautz’s cavalry of the Army of the James, get by Lee’s lines and destroy as much as they could of the Virginia Central Railroad, while, in the mean time, the infantry was to move out so as to protect their rear and cover their retreat back when they should have got through with their work. We were successful in drawing the enemy’s troops to the north side of the James as I expected.