Don't know the dates he served, but there was a

BARR, James H., Co H, Pvt, Pvt

and

BARR, George, Co A, Pvt, Sgt

11th Regiment, Virginia Cavalry
11th Cavalry Regiment was organized in February, 1863, by consolidating the 17th Battalion Virginia Cavalry, one company from the 24th Battalion Virginia Cavalry, and two companies of the 5th Regiment Virginia Cavalry, and two companies of the 5th Regiment Virginia Cavalry. The unit served in W.R. Jones', Lomax's, Rosser's, and J. Dearing's Brigade, Army of Northern Virginia. It was active in the conflicts at Upperville, Fairfield, Bristoe, and Mine Run. Later the regiment participated in The Wilderness Campaign, the defense of Richmond, and Early's Shenandoah Valley operations. It then disbanded as there were no members of the 11th at Appomattox. The field officers were Colonels Oliver R. Funsten and Lunsford L. Lomax, Lieutenant Colonel Matt D. Ball, and Majors William H. Harness and Edward H. McDonald.

Co H - Capt Adolphus Mandeville Pierce's Co; formerly Co C, 24th Bn Va Cav; company organized in Sept 1862; assigned 24th Bn Va Cav [Partisan Rangers] as Co C; Bn disbanded by S.O. No. 3, A&IGO, dated 1/05/1863; this co became Co H, 17th Bn Va Cav as shown by S.O. No. 36, Hdqrs, Army of Northern Virginia, 2/5/1863 & assigned to 11th Regt Va Cav.

Co A - Capt George W. Myer's Co; formerly Co of 7th Regt Va Cav; enlisted 10/7/1861; reorganized 4/22/1862; separated from 7th Regt Va Cav in June 1862; became Co A, 17th Bn Va Cav [known as 1st Bn Va Cav]

Also show a James and Robert Barr serving in Co F, 31st Regt Va Militia [Frederick County].

For his service records, see that rectangle at the top of the page? Clink on it.

JR