| Bronze-and iron-age Celtic-speakers : what don't we know, what can't we know, and what could we know? language, genetics and archaeology in the twenty-first century | Sims-Williams, Patrick | Monograph or Collective Volume | | 2012 |
| Buchedd Beuno: The Middle Welsh Life of St Beuno | | Monograph or Collective Volume | Dublin Institute of Advanced Studies | 2018 |
| Cartography and utilitarianism versus culture : Thomas Colby and the Ordnance Survey of Ireland | McWilliams, Patrick | Article in Journal | | 2008 |
| Celtic civilization : continuity or coincidence? | Sims-Williams, Patrick | Article in Journal | | 2012 |
| Celtomania and celtoscepticism | Sims-Williams, Patrick | Article in Journal | | 1998 |
| Counties of south Ulster, 1834-38 : Cavan, Leitrim, Louth, Monaghan and Sligo | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1998 |
| Cú Chulainn in Wales : Welsh sources for Irish onomastics | Sims-Williams, Patrick | Article in Journal | | 1990 |
| Index to Ordnance Survey Memoirs of Ireland series : people and places | McWilliams, Patrick | Monograph or Collective Volume | Institute of Irish Studies | 2002 |
| Irish influence on medieval Welsh literature | Sims-Williams, Patrick | Monograph or Collective Volume | Oxford University Press | 2011 |
| Larcom the cartographer: political economy in pre-Famine Ireland | McWilliams, Patrick | Article in Journal | | 2008 |
| Leprechauns and Luperci, Aldhelm and Augustine | Sims-Williams, Patrick | Article in Book | | 2015 |
| New approaches to Celtic place-names in Ptolemy's Geography | | Monograph or Collective Volume | Ediciones Clásicas | 2005 |
| Ordnance survey memoirs of Ireland (1830-1840) | McWilliams, Patrick | Article in Journal | | 1992 |
| Owain Glyndŵr's appeal to the Irish lords in 1401 and a Welsh prophecy about a lion in Ireland | Sims-Williams, Patrick | Article in Book | | 2025 |
| Parishes of County Antrim, 1832-8. Vol. 2 : Lisburn and South Antrim | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1991 |
| Parishes of County Antrim, 1838-9. Vol. 1 : Ballymartin, Ballyrobert, Ballywalter, Carnmoney, Mallusk | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1990 |
| Parishes of County Antrim, XIV : 1832, 1839-40 : Carrickfergus | | Monograph or Collective Volume | Queen's University of Belfast, Institute of Irish Studies, in association with the Royal Irish Academy | 1996 |
| Parishes of County Antrim. Vol. 10 : 1830-1, 1833-5, 1839-40 : East Antrim : Glynn, Inver, Kilroot and Templecorran | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1994 |
| Parishes of County Antrim. Vol. 11 : 1832-3, 1835-9 : Antrim town and Ballyclare | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1995 |
| Parishes of County Antrim. Vol. 12 : 1832-3, 1835-40 : Ballynure and district | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1995 |
| Parishes of County Antrim. Vol. 3 : 1833, 1835, 1839-40 : Larne and Island Magee | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1991 |
| Parishes of County Antrim. Vol. 4 : 1830-8 : Glens of Antrim | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1992 |
| Parishes of County Antrim. Vol. 5 : 1830-5, 1837-8 : Giant's Causeway and Ballymoney | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1992 |
| Parishes of County Antrim. Vol. 6 : 1830, 1833, 1835-8 : South West Antrim | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1993 |
| Parishes of County Antrim. Vol. 7 : 1832-8 : South Antrim | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1993 |
| Parishes of County Antrim. Vol. 8 : 1831-5, 1837-8 : Ballymena and West Antrim | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1993 |
| Parishes of County Antrim. Vol. 9 : 1830-2, 1835, 1838-9 : North Antrim coast and Rathlin | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1993 |
| Parishes of County Armagh, 1835-8 | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1990 |
| Parishes of County Donegal. Vol. 1 : 1833-35 : North-east Donegal | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1997 |
| Parishes of County Donegal. Vol. 2 : 1835-36. Mid, west and south Donegal | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1997 |
| Parishes of County Down, 1832-4, 1837. Vol. 2 : North Down and the Ards | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1991 |
| Parishes of County Down, 1834-6. Vol. 1 : South Down | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1990 |
| Parishes of County Down. Vol. 3 : 1833-8 : Mid-Down | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1992 |
| Parishes of County Down. Vol. 4 : 1833-7 : East Down and Lecale | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1992 |
| Parishes of County Fermanagh, 1834-5. Vol. 1 : Enniskillen and Upper Lough Erne | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1990 |
| Parishes of County Fermanagh. Vol. 2 : 1834-5 : Lower Lough Erne | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1992 |
| Parishes of County Londonderry, 1830, 1834, 1836. Vol. 1 : Arboe, Artrea, Ballinderry, Ballyscullion, Magherafelt, Termoneeny | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1990 |
| Parishes of County Londonderry, 1833-5. Vol. 2 : Roe Valley Central | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1991 |
| Parishes of County Londonderry, X : 1833-5, 1838 : Mid-Londonderry | | Monograph or Collective Volume | Queen's University of Belfast, Institute of Irish Studies, in association with the Royal Irish Academy | 1995 |
| Parishes of County Londonderry, XI : 1821, 1833, 1836-7 : South Londonderry | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1995 |
| Parishes of County Londonderry, XII 1829-30, 1832, 1834-36 : Coleraine and Mouth of the Bann | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1995 |
| Parishes of County Londonderry. Vol. 14 : 1833-4, 1836, 1838 : Faughanvale | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1996 |
| Parishes of County Londonderry. Vol. 3 : 1831-5 : Roe Valley Lower | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1991 |
| Parishes of County Londonderry. Vol. 4 : 1824, 1833-5 : Roe Valley Upper | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1992 |
| Parishes of County Londonderry. Vol. 5 : 1830, 1833, 1836-7 : Maghera and Tamlaght O'Crilly | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1993 |
| Parishes of County Londonderry. Vol. 6 : 1831, 1833, 1835-6 : North-East Londonderry | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1993 |
| Parishes of County Londonderry. Vol. 7 : 1834-5. North-west Londonderry | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1994 |
| Parishes of County Londonderry. Vol. 8 : 1830, 1833-7, 1839 : East Londonderry | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1994 |
| Parishes of County Londonderry. Vol. 9 : 1832-8 : West Londonderry | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1995 |
| Parishes of County Tyrone, 1821, 1823, 1831-6. Vol. 1 : North, West and South Tyrone | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1990 |
| Parishes of County Tyrone. Vol. 2 : 1825, 1833-5, 1840 : Mid and East Tyrone | | Monograph or Collective Volume | Institute of Irish Studies in association with the Royal Irish Academy | 1993 |
| Reactions to the Ordnance Survey : a window on prefamine Ireland | McWilliams, Patrick S. | Article in Journal | | 2009 |
| Some problems in deciphering the early Irish Ogam alphabet | Sims-Williams, Patrick | Article in Journal | | 1993 |
| The additional letters of the Ogam alphabet | Sims-Williams, Patrick | Article in Journal | | 1992 |
| The additional letters of the Ogam alphabet | Simms-Williams, Patrick | Article in Journal | | 1992 |
| The Celtic inscriptions of Britain : phonology and chronology, c.400-1200 | Sims-Williams, Patrick | Monograph or Collective Volume | Blackwell Publishers | 2003 |
| The development of the Indo-European voiced labiovelars in Celtic | Sims-Williams, Patrick | Article in Journal | | 1981 |
| The double system of verbal inflexion in Old Irish | Sims-Williams, Patrick | Article in Journal | | 1984 |
| The earliest Celtic ethnography | Sims-Williams, Patrick | Article in Journal | | 2017 |
| The evidence of vernacular Irish literary influence on early medieval Welsh literature | Sims-Williams, Patrick | Article in Book | | 1982 |
| The invention of Celtic nature poetry | Sims-Williams, Patrick | Article in Book | | 1996 |
| The Irish geography of Culhwch and Olwen. | Sims-Williams, Patrick | Article in Book | | 1989 |
| The location of the Celts according to Hecataeus, Herodotus, and other Greek writers | Sims-Williams, Patrick | Monograph or Collective Volume | | 2016 |
| The medieval world of Robin Flower | Sims-Williams, Patrick | Article in Book | | 1998 |
| The Ordnance Survey memoir of Ireland : origins, progress and decline | McWilliams, Patrick | Thesis | | |
| The papacy and episcopal appointments in Ireland, 1305-34 | Williams, Patrick | Thesis | | 1961 |
| The submission of Irish kings in fact and fiction : Henry II, Bendigeidfran, and the dating of The Four Branches of the Mabinogi | Sims-Williams, Patrick | Article in Journal | | 1991 |
| Thought, word, and deed : an Irish triad | Sims-Williams, Patrick | Article in Journal | | 1978 |
| Townlands : a recurrent theme in the ordnance survey memoirs of Ireland | McWilliams, Patrick | Article in Book | | 1991 |