The marker for Welsh’s Brigade of Willcox’s Division is on the east side of Rodman Avenue near Burnside Bridge Road.  (Rodman Avenue tour map)

From the marker:

U.S.A.
Ninth Army Corps

Welsh’s Brigade, Willcox’s Division

Col. Thomas Welsh, 45th Pennsylvania Infantry, Commanding.

Organization.
8th Michigan Infantry,
46th New York Infantry,
45th and 100th Pennsylvania Infantry

September 17, 1862.

On the morning of the 17th Welsh’s Brigade was in reserve on the eastern slope of the ridge on the left bank of the Antietam, nearly opposite the Burnside Bridge. About 2 P.M., after Sturgis’ Division had carried the bridge, the Brigade crossed and, following the road to Sharpsburg about 250 yards, formed line west of the road.

The Brigade then advanced over the high ground west of the road, gradually crossing to the east, until its right was near this point, its center in the ravine and at the stone mill, and its left in the apple orchard beyond, when the attack of A.P. Hill on the left flank of the Corps compelled it to withdraw to the banks of the Antietam, where it remained until the evening of the 18th.

No. 64.