Patrick McMahon was a marine in the 32nd (Portsmouth) Company when he arrived at Sydney aboard the Supply in January 1788 as part of the First Fleet.
McMahon was discharged to the Port Jackson detachment on 20 May 1789 but was sent to Norfolk Island on the Supply in March 1790. He returned to England on the Atlantic in June 1792.
* information from Mollie Gillen, The Founders of Australia: A Biographical Dictionary of the First Fleet (1989), p 233
'McMahon, Patrick (?–?)', People Australia, National Centre of Biography, Australian National University, https://peopleaustralia.anu.edu.au/biography/mcmahon-patrick-31440/text38893, accessed 17 March 2025.