Before starting on the Atlanta campaign the Twelfth Corps was designated the Twentieth, its command being given to General Hooker. The regiment started on that campaign with 380 fighting men, of whom 136 were killed or wounded before reaching Atlanta. Lieutenant-Colonel Charles B. Randall, a gallant and skilful officer, was killed at Peach Tree Creek, in which action the regiment sustained its heaviest loss while on that campaign, its casualties there aggregating 17 killed, 25 wounded, and 10 missing.