| 1859 | January |  Letter from John O'Leary to John O'Mahony, January, 1859, no day |
| September | Letter from John O'Mahony to William Sullivan, September 1, 1859 |
| October | Letter from James Stephens to John O'Mahony, October 17, 1859 |
| 1860 | | A blank form letter for commission in the Army of the Irish Republic |
| | A blank form letter for commission in the Navy of the Irish Republic |
| | A blank form letter for the commission of a naval vessel of the Irish Republic |
| March | Letter from James Cantwell to John O'Mahony, March 27, 1860 |
| April | Letter from James Cantwell to John O'Mahony, April 28, 1860 |
| May | Letter from James Cantwell to John O'Mahony, May 3, 1860 |
| | Letter from Putnam and Diarmaid to John O'Mahony, May 25, 1860 |
| July | Letter from John O'Mahony to P. Murphy, July 13, 1860 |
| August | Letter from E. Bourke to John O'Mahony August 8, 1860 |
| September | Letter from James Johnson (James Stephens) to John O'Mahony, September, 1860 |
| | Letter from James Stephens to John O'Mahony, September 13, 1860 |
| November | Letter from James Cantwell to John O'Mahony, November 2, 1860 |
| 1861 | May | Letter from John Mitchel to John O'Mahony, May 8, 1861 |
| July | Letter from William O'Carroll to John O'Mahony, July, no day, 1861 |
| August | Letter from William O'Carroll to John O'Mahony, August 14, 1861 and August 25, 1861 |
| October | Letter from Edmund O'Flaherty to John O'Mahony, October 5, 1861 |
| November | Letter from John O'Mahony, November 19, 1861 |
| 1862 | April | Letter from J.S. (James Stephens) to John O'Mahony, April 7, 1862 |
| | Letter from J. Kelly (James Stephens) to John O'Mahony, April 11, 1862 |
| | Letter from James Stephens to John O'Mahony, April 22, 1862 |
| | Letter from J. Kelly (James Stephens) to John O'Mahony, April 29, 1862 |
| May | Letter from Charles U. O'Connell to John O'Mahony, May 1, 1862 |
| | Letter from J. Egan (James Stephens) to John O'Mahony, May 30, 1862 |
| July | Letter from Michael Cavanagh to John O'Mahony, July 31-August 2, 1862 |
| August | Letter from Louis Philippe D'Orleans to Colonel Felix Comfort, August 11, 1862 |
