| A concise history of Ireland | O'Brien, C. C.O'Brien, Máire | Monograph or Collective Volume | Thames & Hudson | 1972 |
| Life of St Finbarr : founder and patron of the city and diocese of Cork | O'Brien, C. M. | Monograph or Collective Volume | Killarney Printing Works | 1985 |
| Parnell and his Party, 1880-90 | O'Brien, C. C. | Monograph or Collective Volume | Clarendon Press | 1957 |
| The diary of Edward Colclough Byrne | O'Brien, C.O'Brien, Conor, 1933- | Article in Journal | | 1996 |
| The great melody : a thematic biography and commented anthology of Edmund Burke | O'Brien, C. C. | Monograph or Collective Volume | | 1992 |
| The Irish Parliamentary Party machine, 1874-85 | O'Brien, C. C. | Article in Journal | | 1946 |
| The machinery of the Irish Parliamentary Party, 1880-5 | O'Brien, C. C. | Article in Journal | | 1946 |