On 13 August 1844, Leichhardt’s party sailed from Sydney to Moreton Bay. The party later left Jimbour Station, the farthest outpost settlement on the Darling Downs in the Moreton Bay district on 1 October 1844, travelling north by north-west across the Dawson and Mackenzie valleys. The expedition discovered the Burdekin River, which they followed upstream to the Valley of Lagoons. The party reached Port Essington on 17 December 1845, completing an overland journey of nearly 4,800 kilometres.
Leichhardt has been credited with completing one of the longest journeys of exploration by land in Australia, the discovery of excellent pastoral land and the collection of the data for the earliest map of the country covered by his route.