This marker is one of the roughly two dozen that have disappeared over the years, but records provide its location and text. It was on the south side of Boonsboro Pike, northeast of the Middle Bridge.

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From the marker:
U.S.A.
Sykes Division, Fifth Army Corps
Brig. Gen. George Sykes, Commanding.
(September 15-16, 1862.)
Sykes’ Division reached this point in the afternoon of September 15, 1862, and formed line in the fields to the left of the Boonsboro Pike.
In cooperation with Richardson’s Division of the Second Corps, it supported the Artillery on the ridge in front.
A part of the Division held the approaches to the stone bridge in order to secure the crossing of the Antietam for the movement of September 16.
No. 22.
