Born at Dromoland Castle County Clare, Ireland in 1821, George O'Brien was the fifth son of Admiral Robert O'Brien, a direct descendant of Murrough O'Brien, 57th King of Thomond, and of Brian Boroimhe, Monarch of Ireland. George O'Brien was a cousin of William Smith O'Brien (1803-1864) deported to Tasmania for his part in the 1848 Young Ireland uprising, and was also a cousin of James Fitzgerald, who was at one time Superintendent of the Canterbury Province in New Zealand. Despite these distinguished connections, the family was not well-heeled.

Young George O'Brien may have been trained by a brother as a civil engineer. His parents died when he was young and at an early age he was in Melbourne Australia, where v...