George Martin
O.R.-- SERIES I--VOLUME XXXVIII/3 [S# 74]
May 1-September 8, 1864.--THE ATLANTA (GEORGIA) CAMPAIGN
No. 624.--Report of Col. William Barkuloo, Fifty-seventh Georgia Infantry, commanding Mercer's brigade, of operations July 22-August 2.
p. 759
"July 24, again assumed command of the brigade, then in the trenches southeast of Atlanta, near the Fair Ground road. July 25, in the morning the brigade was assigned to Major-General Cleburne's division, and Brigadier-General Mercer returned to his place. In the evening he was relieved and I again placed in command. July 26, we were occupied in clearing up the ground and completing the works. July 27, at 7.30 a.m. we moved into the trenches south of Atlanta, with the left resting upon the Georgia Railroad." The Georgia RR runs to the SE through Decatur.
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Nearby Atlanta hospitals were the: Fairground Hospitals No. 1 and No. 2, located on the Fairgrounds; General Hospital and Receiving & Wayside Hospital located near the railroad station. In Macon was the Ocmulgee Hospital and the Empire Hospital, relocated sometime in 1864, first to Tuscumbia, Cornith, Meridian and Opelika
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I did a Goggle search "Atlanta Fairground Hospital" and came up with this book "Gangrene and Glory: Medical Care During the American Civil War" - Google Books Result by Frank R. Freemon - 2001 - History - 256 pages Starting on page 152 you will find some interesting information.
[http://books.google.com/booksid=fU_G7ePrFgC&pg=PA153&lpg=PA153&dq=Atlanta+Fairground+Hospital&source=web&ots=3iCpwfcnSj&sig=mAtGuEv8UQiyknPAqAUcuit9qxU&hl=en&sa=X&oi=book_result&resnum=4&ct=result]