Mr. Rutherford,

Without knowing your ancestor's name and the county he lived in during the 1860 Federal Census, I was not sure which of the two regiments he may be in so I have included the information for both. Below are links to capsule histories that are contained in "Tennesseans in the Civil War, Volume 1," and a brief bibliography of each.

6th Tennessee Infantry (US)
http://www.tngenweb.org/civilwar/usainf/usa6inf.html

Dyer, Frederick H. A Compendium of the War of the Rebellion. Vol. 2. Dayton, OH: Morningside,
1979. Ref. See p. 1646 (1 photocopied page) for a concise summary of the regiment's service.

Tennessee. AGO. Report...From 1861 to 1865. Nashville, TN: S.C. Mercer, 1866. See pp. 119-33 (8 photocopied pages) for a roster of the regiment.

Tennessee. CW Centennial Comm. Tennesseans in the Civil War: A Military History of Union and Confederate Units.... Vol. 1. Nashville, TN: By the Commission, 1964. See pp. 387-89 (3 photocopied pages) for a brief history of the unit and a roster of officers.

6th Tennessee Mounted Infantry (US)
http://www.tngenweb.org/civilwar/usacav/usa6minf.html

Dyer, Frederick H. A Compendium of the War of the Rebellion. Vol. 2. Dayton, OH: Morningside, 1979. Ref. See p. 1646 (1 photocopied page) for a concise summary of the regiment's service.

Rule, William. "The Loyalists of Tennessee in the Late War." In Sketches of War History (MOLLUS, OH, Vol. 2). Cincinnati, OH: Robert Clarke, 1888. pp. 180-204 (13 photocopied pages)

Tennessee. AGO. Report...From 1861 to 1865. Nashville, TN: S.C. Mercer, 1866. See pp. 264-76 (7 photocopied pages) for a roster of the regiment.

Tennessee. CW Centennial Comm. Tennesseans in the Civil War: A Military History of Union and Confederate Units.... Vol. 1. Nashville, TN: By the Commission, 1964. See pp. 358-59 (2 photocopied pages) for a brief history of the unit and a roster of officers.

I hope this helps.

Respectfully,

Gerald D. Hodge, Jr.
War Between the States Historian
Historian: 39th Georgia Volunteer Infantry Regiment
http://39thgavolinfrgt.homestead.com/39thHomepage.html