On 3 September 1804 Hamilton was married to Julia Udny, a daughter of Selina Shore Clevland (a daughter of John Clevland MP) and John Udny, the British Consul at Venice and Leghorn.
Hamilton married Julia Udny on September 3, 1804. Julia was the daughter of Selina Shore Clevland (descendant of John Clevland MP), who was a British Consul in Venice and Leghorn, and John Udny.