The marker for the First Battalion (8 Cos.), Fourteenth U.S. Infantry is on the east side of Rodman Avenue, near Boonsboro Pike. (Boonsboro Pike tour map)

From the marker:

U.S.A.
Fifth Army Corps

First Battalion (8 Cos.), Fourteenth U.S. Infantry 

Capt. W. Harvey Brown, 14th U.S. Infantry, Commanding.

September 17, 1862.

At 3 P.M. of the 17th the First Battalion, Fourteenth U.S. Infantry crossed the Antietam at the Middle Bridge and advanced on the Boonsboro Pike until it reached the point where the Bloody Lane enters the Pike (200 yards east of this), where the Battalion was posted on the left (south) of the Pike as a reserve to the 4th U.S. Infantry.

At dusk Companies F and G deployed as skirmishers, advanced to this lane, formed on the right of the Second and Tenth U.S. Infantry, and engaged the Confederate skirmishers in the edge of the cornfield in front.

The Battalion was withdrawn at dark and recrossed the Antietam.

No. 79

See more on the history of the 14th United States Infantry Regiment in the Civil War.