On 20 December 1820 the convict ship Almorah docked at Port Jackson. On board were two Irish convicts – Michael Gannon and his brother James Gannon – who hailed from County of Westmeath, in the province of Leinster. Michael had been sentenced to death, but this was commuted to transportation for life. His brother James had been sentenced to 14 years transportation. The fortunes (or otherwise) of this first generation, of what was to become an extensive Gannon clan, are recounted under their section.
John was the second son of James Gannon. As with the other Gannon children of his generation, he had thrown off the convict shackles. John moved to Goulburn shortly after his marriage and established a flourishing legal practice there and an esteemed reputation as a fine, upstanding member of the community.
The second of four sons of John Thomas Gannon, Samuel was a troublesome lad who grew up to be a rogue. He ended his life, a sad old man, in New Zealand.