| A 1950's Irish childhood : from catapults to communion medals | Illingworth, Ruth | Monograph or Collective Volume | History Press Ireland | 2018 |
| A short history of Mullingar Town Council from foundation to dissolution, 1856-2014 | Illingworth, Ruth | Monograph or Collective Volume | Westmeath County Council | 2014 |
| Alan Turing : the genius who changed the world | Illingworth, Ruth | Article in Journal | | 2013 |
| Canal and rail transport in Longford | Illingworth, Ruth | Article in Journal | | 2006 |
| Colonel Howard Bury | Illingworth, Ruth | Article in Journal | | 1991 |
| Images of Mullingar | Illingworth, Ruth | Monograph or Collective Volume | History Press | 2008 |
| Kenneth Edgeworth, astronomer | Illingworth, Ruth | Article in Journal | | 2008 |
| Modern Mullingar, 1923-1993 | Illingworth, Ruth | Article in Book | Geography Publications | 2022 |
| Mullingar : history & guide | Illingworth, Ruth | Monograph or Collective Volume | Nonsuch | 2007 |
| Mullingar in 1916 | Illingworth, Ruth | Article in Journal | | 2017 |
| Mullingar Town Commissioners | Illingworth, RuthÓ Conláin, Mícheál | Article in Book | | 2002 |
| Sheelagh Murnaghan, 1924-1993 : Stormont's only Liberal MP | Illingworth, Ruth | Monograph or Collective Volume | Ulster Historical Foundation | 2019 |
| Transport, 1806-1905 | Illingworth, Ruth | Article in Book | | 2002 |