The marker for Battery A, 5th U.S. Artillery is on the east side of Branch Avenue. (Branch Avenue South tour map)
From the marker:
U.S.A.
Battery A, 5th U.S. Artillery
Lieut. Chas. P. Muhlenburg, U.S.A., Commanding.
(September 17, 1862.)
On the morning of the 17th, Battery A was in position on the crest of the hill east of the Rohrbach Lane, east of and overlooking the stone bridge over the Antietam. In the afternoon the Battery crossed the bridge and went into position on the ridge 730 yards a little south of and east of this point and engaged the Confederate artillery and infantry. Later in the day the battery moved about 60 yards west and 100 yards south of its first position, more effectually to check a flank movement of A.P. Hill’s Division. At night the battery was withdrawn to the cover of the ridge on which it had been engaged.
No. 112.

The view looks east from Branch Avenue across the Otto farm fields. The monument to the 16th Connecticut Infantry is in the distance.