The War Department marker for Patrick’s Bivouac is on the east side of Mansfield Avenue near its intersection with the Hagerstown Pike. (Mansfield Avenue tour map) This marker is the first of three telling the story of Patrick’s Brigade on the Antietam battlefield. The second marker is on the east side of Maryland Route 65, north of Starke Avenue.

From the marker:

U.S.A.
Patrick’s Brigade
First Army Corps

On the night of September 16, 1862, Patrick’s Brigade of Doubleday’s Division bivouacked in line of battle on the east side of this road, facing west.

This tablet marks the left of the brigade line, which extended northerly about 320 yards, through a triangular strip of woods.