President Lincoln and group of civil war officers at Antietam, Maryland, 1862.

President Lincoln with General George B. McClellan (#6) and a group of officers at Antietam, Maryland. Photograph from the main eastern theater of the civil war, Battle of Antietam, September–October 1862.
CLICK FOR FULL-SIZE PICTURE

From Left to Right:

01. Colonel Delos B. Sackett, I.G. 

02. Captain George Monteith. 

03. Lieutenant Colonel Nelson B. Sweitzer. 

04. General George W. Morell. 

05. Colonel Alexander S. Webb, Chief of Staff, 5th Corps. 

06. General George B. McClellan. 

07. Scout Adams. 

08. Dr. Jonathan Letterman, Army Medical Director. 

09. Unknown. 

10. President Lincoln. 

11. General Henry J. Hunt. 

12. General Fitz-John Porter. 

13. Unknown. 

14. Colonel Frederick T. Locke, A.A.G. 

15. General Andrew A. Humphreys. 

16. Captain George Armstrong Custer.