| "Ulster's midwife" : Sir Ernest Clark and the birth of the Northern Ireland administration | McColgan, John | Article in Journal | | 1990 |
| Acta santorum veteris et majoris Scoticae seu Hiberniae sanctorum insulae. Tomus primus ... Januarium, Februarium et Martium complectens | Colgan, John | Monograph or Collective Volume | The Stationery Office | 1948 |
| Boston in the Famine : city government and the emigrant crisis | McColgan, John | Article in Book | | 2022 |
| Boston's Donegal diaspora | McColgan, John | Article in Journal | | 2019 |
| British Cabinet Office Records and the Partition of the Irish Administration | McColgan, John | Article in Journal | | 1974 |
| British Policy and the Irish Administration, 1920-22 | McColgan, John | Monograph or Collective Volume | Allen & Unwin | 1983 |
| Documents and sources : abstracts from Dublin to Mullingar Turnpike Commissioners/Trustees minute books | Colgan, John | Article in Journal | | 1994 |
| Four Latin lives of St Patrick : Colgan's 'Vita Secunda' , 'Quarta', 'Tertia' and 'Quinta' | Bieler, LudwigColgan, John | Monograph or Collective Volume | Institute for Advanced Studies | 1971 |
| Hillsborough House near Droichead Nua | Colgan, John | Article in Journal | | 2003 |
| Implementing the 1921 Treaty : Lionel Curtis and Constitutional Procedure | McColgan, John | Article in Journal | | 1977 |
| Leixlip - Confey gravestones | Colgan, JohnCormack, David | Article in Journal | | 2004 |
| Leixlip, county Kildare, vol.1 | Colgan, John | Monograph or Collective Volume | Tyrconnell Press | 2005 |
| Macallaí i Meiriceá : Scéal eirí amach na Cásca i nuachtáin na Stát Aontaithe | McColgan, JohnRowlands-Tarbox, Jean | Monograph or Collective Volume | Coiscéim | 2016 |
| Masons' marks on the Liffey Bridge at Leixlip | Colgan, John | Article in Journal | | 2000 |
| Nathaniel Colgan 1851-1919: the life times and genealogy of an enigmatic Dubliner | Colgan, John
| Monograph or Collective Volume | Four Courts Press | 2022 |
| Nathaniel Colgan, 1851-1919 : the life, times and genealogy of an enigmatic Dubliner | Colgan, John | Monograph or Collective Volume | Four Courts Press | 2022 |
| Notes & queries : the Franciscan friar John Colgan's Offaly roots | Colgan, John F. | Article in Journal | | 2011 |
| Partition and the Irish administration, 1920-22 | McColgan, John | Article in Journal | | 1980 |
| St. Mary's Leixlip gravestone inscriptions | Colgan, John | Article in Journal | | 2003 |
| The Irish administration in transition : British administrative policies in Ireland, 1920-1922 | McColgan, John J. | Thesis | | 1976 |
| Triadis thaumaturgae, seu divorum Patricii, Columbae, et Brigidae ... acta | Colgan, John | Monograph or Collective Volume | | 1647 |
| Trias Thaumaturga | Colgan, John | Monograph or Collective Volume | De Búrca | 1997 |