The rebel army under the command of General Joseph E. Johnston, abandoned their works around Kenesaw Mountain, Georgia, on the evening of July 1st 1864 and began a retreat towards Marietta with Union General William T. Sherman's bluecoats in close pursuit. For the next several days, the 55th Ohio, along with its brigade, marched after the rebels and had several brushes with the enemy's skirmishers. General Sherman continuously outflanked the Confederates, forcing them to fall further and further back towards Atlanta. By the 18th of July the 55th Ohio, along with its brigade, arrived near Buck Head and occupied the area until the 20th. On that date the 55th's brigade crossed Peachtree Creek to fill a gap in the 20th Corps line. Once in position, the men were ordered to stack arms and rest for awhile. At 3:00 p.m. it was learned that the rebels were making an advance towards the Union positions. The rattle of musketry on the skirmish line announced that the report was true and the men were ordered forward at once.
Confederate General John Bell Hood had replaced General Johnston three days earlier, and he had decided to attack the 4th and 20th Corps. Colonel James Wood, who commanded the 3rd brigade, 3rd Division, 20th Corps wrote: "Over the crest of the hill, down into the ravine on the other side, the line advanced as it emerged from a fringe of trees or bushes…. it met the enemy". The withering fire of this brigade drove the rebels back and brigade pursued them to the next hill. "I ordered the 55th Ohio to re-inforce the line on the left, as there was a gap (between the 20th Connecticut and the 4th Corps). The commanding officer of the 55th Ohio (Lt. Col. Powers) very properly and judiciously with his regiment filed the gap… the men (of the brigade) took positions behind (a) fence and kept up a constant and continuous fire upon the enemy. The enemy made one or two ineffectual attempts to renew the attack, but his troops would not or could not withstand the destructive fire which ours kept upon them from our line, and he gave up the contest and retreated behind his strong and well-protected line of earthworks… To us it was a brilliant feat of arms. We encountered the enemy in superior numbers in the open field. We met his offensive attack with an offensive return… The victory was complete and decisive… The men and officers of the brigade sustained their well-earned reputation for bravery and gallantry." Hood's rebels sustained significant loss, being everywhere decisively repulsed. According to Lt. Col. Powers, the 55th lost "between 20 and 30 men".
By the 22nd of July, the 55th and its brigade moved to within two miles of Atlanta and commenced siege operations of that city. On July 28th, having felt that he was unfairly passed over for promotion, General "Fighting Joe" Hooker resigned as commander of the 20th Corps. Major General Henry Slocum was recalled from Vicksburg to replace him as commander.
Sources Trials and Triumphs by Hartwell Osborne, 1904
All Brave and True by Dan Munson, 1986