66th OHIO INFANTRY REGIMENT
Organized at Camp McArthur, Urbana, Ohio, and mustered in Dec. 17, 1861. Ordered to New Creek, W. Va., Jan. 17, 1862.
Advance toward Winchester, Va., March 7-15, 1862. Provost duty at Martinsburg, Winchester and Strasburg till May. March to Fredericksburg, Va., May 12-21, and to Port Republic May 25-June 7. Battle of Port Republic June 9. Ordered to Alexandria and there until August. Operations near Cedar Mountain Aug. 10-18. Pope's Campaign in Northern Virginia Aug. 18-Sept. 2. Guarding trains of the army during the battles of Bull Run Aug. 28-30. Maryland Campaign Sept. 6-22. Battle of Antietam Sept. 16-17. at Bolivar Heights until December. Reconnoissance to Rippon, W. Va., Nov. 9. Reconnoissance to Winchester Dec. 2-6. Berryville Dec. 1. Dumfries Dec. 27. "Mud March" Jan. 20-24, 1863. At Stafford Court House until April 27. Chancellorsville Campaign April 27-May 6. Battle of Chancellorsville May 1-5. Gettysburg, Pa. Campaign June 11-July 24. Battle of Gettysburg July 1-3. Pursuit of Lee to Manassas Gap, Va., July 5-24. at New York during draft disturbances Aug. 15-Sept. 8. Movement to Bridgeport, Ala., Sept. 24-Oct. 3. Skirmish at Garrison's Creek near Fosterville Oct. 6 (Detachment). Reopening Tennessee River Oct. 26-29. Chattanooga-Ringgold Campaign Nov. 23-27. Lookout Mountain Nov. 23-24. Mission Ridge Nov. 25. Ringgold Gap, Taylor's Ridge, Nov. 27. Regiment reenlisted Dec. 15, 1863. Duty at Bridgeport and in Alabama until May 1864. Scout to Caperton's Ferry March 29-April 2. Expedition from Bridgeport down Tennessee River to Triana April 12-16. Atlanta, Ga. Campaign May 1-Sept. 8. Demonstrations on Rocky Faced Ridge May 8-11. Dug Gap or Mill Creek May 8. Battle of Resaca May 14-15. Cassville May 19. New Hope Church May 25. Operations on line of Pumpkin Vine Creek and battles about Dallas, New Hope Church and Allatoona Hills May 25-June 5. Operations about Marietta and against Kenesaw Mountain June 10-July 2. Pine Hill June 11-14. Lost Mountain June 15-17. Gilgal or Golgotha Church June 15. Muddy Creek June 17. Noyes Creek June 19. Kolb's Farm June 22. Assault on Kenesaw June 27. Ruff's Station July 4. Chattahoochie River July 5-17. Peach Tree Creek July 19-20. Siege of Atlanta July 22-Aug. 25. Operations at Chattahoochie River Bridge Aug. 26-Sept. 2. Occupation of Atlanta Sept. 2-Nov. 15. Near Atlanta Nov. 9. March to the sea Nov. 15-Dec. 10. Siege of Savannah Dec. 10-21. Campaign of the Carolinas January to April, 1865. Little Cohora Creek, N. C., March 16. Battle of Bentonville March 19-21. Occupation of Goldsboro March 24. Advance on Raleigh April 10-14. Occupation of Raleigh April 14. Bennett's House April 26. Surrender of Johnston and his army. March to Washington, D.C., via Richmond, Va., April 29-May 20. Grand Review May 24. Moved to Louisville, Ky., June, and there mustered out July 15, 1865. Regiment lost five officers and 96 enlisted men killed or died of wounds and one officer and 143 enlisted men died of disease or other non-battle causes=245.
Source: Dyer, Frederick, Compendium of the War of the Rebellion Vol. III

66th Ohio under Ltcol. Eugene Powell mentioned in Harry Pfanz's "Cemetery and Culp Hill", a detailed account of the fighting there as part of the battle of Gettysburg. Col. Charles Candy of 66th Ohio was the brigade commander.

The regiment, Col. Candy and LtCol. Powell mentioned in Peter Cozzens "The Shipwreck of their Hopes (battles about Chattanooga). Both books fairly new so local library may have them or at least can get them through inter-library loan.