In April 1864, Battery I, 1st U.S. Artillery was merged with Battery H, 1st U.S. Artillery, creating the combined Battery H &amp; I, 1st U.S. Artillery under Randol's command. In May 1864, Battery H &amp; I joined Major General Ulysses S. Grant's Overland Campaign, present during the battles of the Wilderness and Spotsylvania Courthouse with the Artillery Reserve and later attached to the Second Division of the Cavalry Corps, Army of the Potomac in June. It was present during the battles at Cold Harbor through St. Mary's Church. By July, the battery was mostly in camp refitting following heavy materièl losses sustained during the campaign, rejoining Gregg's division on July 25 at the Battle of First Deep Bottom, then present near the Battle of the Crater (referred to by Randol as the "mine fiasco") and Battle of Lee's Mill through July 30.