Organization of the Army of the Ohio, Maj. Gen. D. C. Buell commanding, April 30, 1862.1
| First Division.2 |
| Brig. Gen. George H. Thomas. |
| First Brigade. | Third Brigade. |
| Brig. Gen. A. Schoepf. | Col. R. L. Mccook. |
| 12th Kentucky, Col. W. A. Hoskins. | 2d Minnesota, Col. James George. |
| 17th Ohio, Col. J. M. Connell. | 9th Ohio, Lieut. Col. G. Kammerling. |
| 31st Ohio, Col. M. B. Walker. | 35th Ohio, Col. F. Van Derveer. |
| 38th Ohio, Col. E. H. Phelps. | 18th U. S., Lieut. Col. O. L. Shepherd. |
| Second Brigade. | Unattached. |
| Brig. Gen. S. S. Fry. | 4th Michigan Battery, Capt. A. F. Bidwell. |
| 10th Indiana, Maj. A. O. Miller. |
| 10th Kentucky, Col. J. M. Harlan. | 1st Ohio, Battery C, Capt. D. Kenny, jr. |
| 4th Kentucky, Col. J. T. Croxton. | 4th U. S. Artillery, Battery I, Capt. O. A. Mack. |
| 14th Ohio, Col. J. B. Steedman. |
| Second Division. |
| Brig. Gen. Alexander McD.
McCook. |
| Fourth Brigade. | Sixth Brigade. |
| Brig. Gen. L. H. Rousseau. | Brig. Gen. R. W. Johnson. |
| 6th Indiana, Col. T. T. Crittenden. | 32d Indiana, Col. August Willich. |
| 5th Kentucky, Col. H. M. Buckley. | 39th Indiana, Col. T. J. Harrison. |
| 1st Ohio, Col. B. F. Smith. | 15th Ohio, Col. M. R. Dickey. |
| 15th U. S. (battalion), Maj. J. H. King. | 49th Ohio, Col. W. H. Grison. |
| 16th U. S. (batt'n), Capt. E. F. Townsend. | Unattached. |
| 19th U. S. (batt'n), Maj. S. D. Carpenter. |
| Fifth Brigade. | Kentucky Battery, Capt. D. C. Stone. |
| Ohio Battery, Capt. W. F. Goodspeed. |
| Pennsylvania Battery, Capt. C. F. Mueller. |
| Col. E. N. Kirk. | 5th U. S. Art'y, Battery H, Capt. W. R. Terrill. |
| 34th Illinois, Lieut. Col. Amos Bosworth. | Indiana Cavalry, Captain Gaddis. |
| 29th Indiana, Lieut. Col. D. M. Dunn. | 2d Kentucky Cav., Col. Buckner Board. |
| 30th Indiana, Col. S. S. Bass. | 1st Michigan Engineers (detachment), Col. W. P. Innes. |
| 77th Pennsylvania, Col. F. S. Stumbaugh. |
| Third Division.3 |
| Maj. Gen. Ormsby M. Mitchel. |
| Eighth Brigade. | Seventeenth Brigade. |
| Col. J. B. Turchin, 19th Illinois. | Col. W. H. Lytle, 10th Ohio. |
| 19th Illinois, Col. J. B. Turchin. | 42d Indiana, Col. J. G. Jones. |
| 24th Illinois, Col. G. Mihalotzy. | 15th Kentucky, Col. C. Pope. |
| 37th Indiana, Col. C. Gazlay. | 3d Ohio, Col. John Beatty. |
| 18th Ohio, Col. T. R. Stanley. | 10th Ohio, Col. W. H. Lytle. |
| Ninth Brigade. | Unattached. |
| Col. J. W. Sill, 33d Ohio | Indiana Battery, Capt. P. Simonson. |
| Michigan Battery, Capt. C. O. Loomis. |
| 2d Ohio, Col. L. A. Harris. | Ohio Battery, Capt. W. P. Edgarton. |
| 21st Ohio, Col. J. S. Norton. | 4th Ohio Cavalry, Col. John Kennett. |
| 33d Ohio, Col. J. W. Sill. | 1st Michigan Engineers (two companies), Capt. J. B. Yates. |
| 10th Wisconsin, Col. A. R. Chapin. |
| Fourth Division.4 |
| Brig. Gen. William Nelson. |
| Tenth Brigade. | Twenty-second Brigade. |
| Col. Jacob Ammen, 24th Ohio. | Col. S. D. Bruce, 20th Kentucky. |
| 36th Indiana, Col. William Grose. | 31st Indiana, Col. Charles Cruft. |
| 17th Kentucky, Col. J. H. McHenry. | 1st Kentucky, Col. D. A. Enyart. |
| 6th Ohio, Col. W. K. Bosley. | 2d Kentucky, Col. T. D. Sedgewick. |
| 24th Ohio, Col. Jacob Ammen. | 20th Kentucky, Col. S. D. Bruce. |
| Nineteenth Brigade. | Unattached. |
| Col. William B. Hazen, 41st Ohio. | 7th Indiana Battery, Capt. S. J. Harris. |
| 10th Indiana Battery, Capt. J. B. Cox. |
| 9th Indiana, Col. G. C. Moody. | 1st Ohio Artillery, Battery D, Capt. A. J. Konkle. |
| 6th Kentucky, Col. W. C. Whitaker. |
| 27th Kentucky, Col. C. D. Pennebaker. | 2d Ind. Cav., Lieut. Col. E. M. McCook. |
| 41st Ohio, Col. W. B. Hazen. | 3d Indiana Cavalry (one company). |
| Fifth Division.5 |
| Brig. Gen. T. L. Crittenden. |
| Eleventh Brigade. | Unattached. |
| Brig. Gen. J. T. Boyle. | Indiana Battery, Capt. Fred. Behr.6 |
| Michigan Battery, Capt. J. J. Dennis. |
| 9th Kentucky, Col. B. C. Grider. | Ohio Battery, Capt. Joseph Bartlett. |
| 13th Kentucky, Col. E. H. Hobson. | 4th U. S. Artillery, Battery M, Capt. John Mendenhall. |
| 21st Kentucky, Col. E. L. Dudley. |
| 19th Ohio, Col. Samuel Beatty. | 4th U. S. Art., Bat. H, Lieut. C. C. Parsons. |
| 59th Ohio, Col. J. P. Fyffe. | 3d Kentucky Cavalry, Col. J. S. Jackson. |
| Sixth Division.7 |
| Brig. Gen. T. J. Wood. |
| Fifteenth Brigade. | ----Brigade |
| Col. M. S. Hascall. | Brig. Gen. W. T. Ward. |
| 17th Indiana, Lieut. Col. J. T. Wilder. | 28th Kentucky, Col. W. P. Boone. |
| 58th Indiana, Col. H. M. Carr. | 11th Michigan, Col. W. L. Stoughton. |
| 13th Michigan, Col. M. Shoemaker. | |
| 26th Ohio, Col. E. P. Fyffe. | |
| Seventh Division.8 |
| Brig. Gen. George W. Morgan. |
| Twenty-fourth Brigade. | Twenty-sixth Brigade. |
| Brig. Gen. S. P. Carter. | Col. John F. De Courcy. |
| 49th Indiana, Lieut. Col. James Keigwin. | 22d Kentucky, Col. D. W. Lindsey. |
| 7th Kentucky, Col. T. T. Garrard. | 16th Ohio, Lieut. Col. G. W. Bailey. |
| 1st Tennessee, Col. R. K. Byrd. | 42d Ohio, Col. L. A. Sheldon. |
| 2d Tennessee, Col. J. P. T. Carter. | |
| Twenty-fifth Brigade. | Twenty-seventh Brigade. |
| Brig. Gen. J. G. Spears. | Brig. Gen. Absalom Baird. |
| 3d Tennessee, Col. L. C. Houk. | 33d Indiana, Col. John Coburn. |
| 4th Tennessee, Col. Robert Johnson. | 14th Kentucky, Col. J. C. Cochran. |
| 5th Tennessee, Col. James T. Shelley. | 19th Kentucky, Col. W. J. Landram. |
| 6th Tennessee, Col. James A. Cooper. | |
| Unattached. |
| 7th Michigan Battery, Capt. C. H. Lanphere. |
| 9th Ohio Battery, Capt. H. S. Wetmore. |
| 1st Wisconsin Battery, Capt. J. T. Foster. |
| 1st Kentucky Battalion Cavalry, Lieut. Col. Reuben Munday. |
| Engineer company, Capt. William Patterson. |
| unassigned to divisions. |
| 18th Kentucky, Col. W. A. Warner. |
| 4th Indiana Battery, Capt. A. K. Bush. |
| 11th Indiana Battery, Capt. A. Sutermeister. |
| 12th Indiana Battery, Capt. G. W. Sterling. |
| Ohio Battery, Capt. C. Bradley. |
| Wisconsin Battery, Capt. L. H. Drury. |