Atlanta campaign order of battle: First phase, Union

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Atlanta campaign order of battle: First phase, Union

Overview
This summary covers the Union Army’s forces and commanders in the Atlanta campaign from May 7 to July 17, 1864. The Confederate order of battle is listed separately. The second phase (July 17–Sept 8, 1864) is in a separate section of the full article.

Command structure
- Overall command: Major General William T. Sherman, Military Division of the Mississippi.
- Army of the Cumberland: commanded by Major General George H. Thomas. This was the main Union force in front of and around Atlanta.
- Army of the Tennessee: commanded by Major General James B. McPherson. This army operated to the south and east of Atlanta, supporting the push toward the city.
- Army of the Ohio (XXIII Corps): commanded by Major General John M. Schofield. This force provided additional capacity and covered southern approaches.
- Cavalry: Several cavalry units supported the main armies, including Washington Elliott as Cavalry Chief of the Army of the Cumberland, plus other cavalry detachments and Stoneman’s Cavalry Division under George Stoneman.

Major formations and roles
- Army of the Cumberland (Thomas)
- IV Corps, XIV Corps, XX Corps: These three infantry corps formed the core of Thomas’s Army of the Cumberland, implementing the advance toward Atlanta and defending critical sectors.
- Cavalry Corps: Provided reconnaissance, screening, and harassment of Confederate movements.
- Army of the Tennessee (McPherson)
- XV Corps, XVI Corps, XVII Corps: These three infantry corps operated to move around the Confederate left flank, screen flanks, and support the main push toward Atlanta.
- Stoneman’s Cavalry Division (attached at times): Conducted raids and reconnaissance to disrupt Confederate rail and supply lines.
- Army of the Ohio (XXIII Corps, Schofield)
- Provided additional infantry divisions to broaden the Union offensive, protect lines of communication, and cooperate with Sherman’s forces around Atlanta.

Strength and manpower
- At the start, Union forces around Atlanta totaled roughly 110,000–113,000 men.
- By late June and into July, numbers declined as units moved, were reorganized, or sent to other duties, with total strength dropping to about 92,000 by late July and around 82,000 by late August.

Notes
- This is a simplified, easy-to-read version focused on the first phase of the Atlanta campaign. The full article includes detailed breakdowns of divisions, brigades, batteries, and individual regiments within each corps and division, as well as notes on command changes and detachments.
- The second phase of the campaign (July 17 to September 8, 1864) is listed separately in the full order of battle.