From Dyer's Compendium

66th Regiment Infantry. Organized at Camp McArthur, Urbana, Ohio, and mustered in December 17, 1861. Ordered to New Creek, W. Va., January 17, 1862. Attached to 3rd Brigade, Landers' Division, Army of the Potomac, to March, 1862. 2nd Brigade, Shields' 2nd Division, Banks' 5th Army Corps and Dept. of the Shenandoah, to May, 1862. 2nd Brigade, Shields' Division, Dept. of the Rappahannock, to June, 1862. 2nd Brigade, 1st Division, 2nd Corps, Army of Virginia, to August, 1862. 1st Brigade, 2nd Division, 2nd Corps, Army of Virginia, to September, 1862. 1st Brigade, 2nd Division, 12th Army Corps, Army of the Potomac, to October, 1863, and Army of the Cumberland to April, 1864. 1st Brigade, 2nd Division, 20th Army Corps, Army of the Cumberland, to July, 1865.

SERVICE.--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 duty there till August. Operations near Cedar Mountain August 10-18. Pope's Campaign in Northern Virginia August 18-September 2. Guarding trains of the army during the battles of Bull Run August 28-30. Maryland Campaign September 6-22. Battle of Antietam September 16-17. Duty at Bolivar Heights till December. Reconnoissance to Rippon, W. Va., November 9. Reconnoissance to Winchester December 2-6. Berryville December 1. Dumfries December 27. "Mud March" January 20-24, 1863. At Stafford Court House till 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. Duty at New York during draft disturbances August 15-September 8. Movement to Bridgeport, Ala., September 24-October 3. Skirmish at Garrison's Creek near Fosterville October 6 (Detachment). Reopening.Tennessee River October 26-29. Chattanooga-Ringgold Campaign November 23-27. Lookout Mountain November 23-24. Mission Ridge November 25. Ringgold Gap, Taylor's Ridge, November 27. Regiment reenlisted December 15, 1863. Duty at Bridgeport and in Alabama till 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-September 8. Demonstrations on Rocky Face 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-August 25. Operations at Chattahoochie River Bridge August 26-September 2. Occupation of Atlanta September 2-November 15. Near Atlanta November 9. March to the sea November 15-December 10. Siege of Savannah December 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 during service 5 Officers and 96 Enlisted men killed and mortally wounded and 1 Officer and 143 Enlisted men by disease. Total 245.

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William K McCormick