- MONAGHAN ASSOCIATES LIMITED- 04975440 - Incorporated on 25 November 2003 
- MONAGHAN BEAUTY LIMITEDDissolved- 07315809 - Dissolved on 14 January 2014 
- KIRBY-MONAGHAN LIMITEDActive - Proposal to Strike off- 07936561 - Incorporated on 6 February 2012 
- MONAGHAN PLANCK LIMITED- 07568377 - Incorporated on 17 March 2011 
- MONAGHAN & STEWART LTD.Dissolved- SC290826 - Dissolved on 10 October 2014 
- DOTTIE MONAGHAN LIMITED- 09159807 - Incorporated on 4 August 2014 
- MONAGHAN FABRICATIONS LIMITEDDisolved- 11005098 - Dissolved on 17 January 2023 
- MONAGHAN COSGROVE LTDDisolved- NI669945 - Dissolved on 26 July 2022 
- MONAGHAN ELECTRICAL LTDDisolved- 09968263 - Dissolved on 4 June 2024 
- HOWARD MONAGHAN LIMITEDActive - Proposal to Strike off- 10124489 - Incorporated on 14 April 2016 
- MONAGHAN GROUNDWORKS LIMITEDDisolved- 13168205 - Dissolved on 11 April 2023 
- MONAGHAN SOUNDS LTDDisolved- 16029098 - Dissolved on 11 March 2025 
- MONAGHAN MACHINERY LTD- NI657017 - Incorporated on 9 November 2018 
- MONAGHAN EXCAVATIONS LIMITED- 10026254 - Incorporated on 25 February 2016 
- MONAGHAN CONSTRUCTION LTD- SC526723 - Incorporated on 12 February 2016 
- AJC MONAGHAN LIMITED- 11960645 - Incorporated on 24 April 2019 
- MONAGHAN MARKETING LIMITEDDisolved- SC272155 - Dissolved on 7 December 2021 
- MONAGHAN PLANT LIMITEDDissolved- 04959670 - Dissolved on 13 March 2012 
- GD MONAGHAN LIMITEDActive - Proposal to Strike off- 06391318 - Incorporated on 5 October 2007 
- MONAGHAN HOTELS LIMITEDLiquidation- SC058621 - Incorporated on 19 September 1975