The monument to the 23rd Ohio Infantry Regiment at Antietam is on Branch Avenue. It was dedicated in 1903.
From the front of the monument:
Commanded by Major James M. Comly
Hugh Ewing's (1st) Brigade
Ninth Army Corps
Army of the Potomac
From the rear of the monument:
This Regiment with its Brigade crossed the Ford of Antietam Creek in the afternoon of Sept. 17, 1862, and held this position until the close of the battle.
Its loss was 8 men killed, 1 officer and 58 men wounded, 2 men missing, total 69.
Two of its members afterwards became President of the United States: Rutherford B. Hayes and William McKinley.
Preseident McKinley is honored by a monument near Burnside's Bridge.
See more about the 23rd Ohio Infantry in the Civil War