The marker for the Artillery of Doubleday’s Division is on the west side of Hagerstown Pike, north of the North Woods. (Mansfield Avenue tour map)

Artillery, Doubleday's Division, marker 25 of the War Department Union markers at Antietam

From the marker:

U.S.A.
First Army Corps

Artillery, Doubleday’s Division

Capt. J. Albert Monroe, 1st R. I. Light Artillery, Commanding.

Organization.

1st New Hampshire Battery
Battery D 1st Rhode Island Light Artillery
Battery L New York Light Artillery
Battery B 4th United States Artillery

September 16, 1862.

The Artillery of Doubleday’s Division went into position on the night of Sept. 16, 1862, on the high plateau about 225 yards east of this point. During the night the First New Hampshire Battery was advanced to within a few feet of this point; one gun was brought into this road.

No. 25.