The marker for the Third Brigade of the Cavalry Division of the Army of the Potomac is on the north side of Boonsboro Pike west of Rodman Avenue. (Boonsboro Pike tour map)

A monument to Colonel James Childs, killed commanding the 4th Regiment of the brigade, is across the highway.

From the marker:

U.S.A.

Third Brigade, Cavalry Division 

Col. Richard H. Rush, 6th Pennsylvania Cavalry,
Commanding.

Organization.
4th and 6th Pennsylvania Cavalry

(September 17, 1862.)

The Third Brigade supported Battery “A” (Tidball’s) 2d U.S. Artillery in its advance, piece by piece, to the crest of the ridge in front, by deploying on either side of this road, – the 4th Pennsylvania on the right, and the 6th on the left – and forcing back the Confederate skirmishers. Col. James A. Childs, commanding 4th Regiment, when on the road a few yards east of this point, was mortally wounded by a rifled shot. The Brigade was relieved by the advance of the Regular Infantry late in the afternoon.

No. 91.