| Regimental number | 2143 |
| Place of birth | Sandy Creek, Victoria |
| Religion | Roman Catholic |
| Occupation | Labourer |
| Address | Sandy Creek via Huon, Victoria |
| Marital status | Single |
| Age at embarkation | 26 |
| Height | 5' 5.25" |
| Weight | 146 lbs |
| Next of kin | Father, John McMahon, Sandy Creek via Huon, Victoria |
| Previous military service | Nil |
| Enlistment date | |
| Place of enlistment | Melbourne, Victoria |
| Rank on enlistment | Private |
| Unit name | 8th Light Horse Regiment, 15th Reinforcement |
| AWM Embarkation Roll number | 10/13/4 |
| Embarkation details | Unit embarked from Melbourne, Victoria, on board HMAT A43 Barunga on |
| Rank from Nominal Roll | Private |
| Unit from Nominal Roll | 8th Mobile Veterinary Section |
| Fate | Returned to Australia |
| Miscellaneous details (Nominal Roll) | Date of return to Australia incorrectly entered on Nominal Roll as 10 March 1919. |
| Discharge date | |
| Family/military connections | Brothers: 3202 Pte James McMAHON, 7th Bn, killed in action, 24 July 1916; 3203 Pte John McMAHON, 57th Bn, killed in action, 24-25 April 1918. |
| Other details |
War service: Egypt, Palestine Commenced return to Australia from Suez on board HT 'Euripides', 15 March 1919; disembarked Melbourne, 25 April 1919; discharged (medically unfit: pleurisy), Melbourne,9 June 1919. Medals: British War Medal, Victory Medal |
| Sources | NAA: B2455, McMAHON Thomas Edward |