Setting off on 1 October, Leichhardt’s lengthy and detailed journal recorded the epic journey through 3,000 miles (4,800km) of country almost entirely unknown to Europeans. By the time they reached Port Essington over 14 months later on 17 December 1845, the party had long been given up as lost. He had completed one of the longest journeys of exploration in Australia’s European history and returned to a hero’s welcome, his discoveries of expansive pastoral lands causing great excitement throughout the colony.
A year later Leichhardt set out again, leaving Moreton Bay in December 1846. This expedition received some government funding to supplement private subscriptions, its optimistic intention to cross the continent from east to west, from the Darling Downs to the Swan River settlement of Perth. However the party, beset by multiple difficulties with flooding rains, dwindling provisions and malarial fever, returned after seven months in June 1847, having penetrated only 800km into the interior of the country.
After recovering, Leichhardt undertook another lengthy expedition on the western Darling Downs and beyond, tracing the course of the Condamine River and charting a large tract of previously unknown country. His thorough documentation of his journeys and his scientific findings won him recognition in Europe.
On his return, he learned he was one of two people awarded the Paris Geographical Society’s annual prize for 1847. His expedition to Port Essington also won him the Patron’s Medal of the Royal Geographical Society in London for the “increased knowledge of the great continent of Australia” which it had generated. The latter medal is now in the possession of the National Museum of Australia.
His vision of crossing the continent had not died. In March 1848 he set out once more from the Condamine River and, with his departure from Coogoon Station in the Maranoa on 3 April 1848, this was to be the last recorded sighting of Ludwig Leichhardt and his party.
Several government expeditions mounted over several years to solve the mystery met with no success. The only clues were several trees marked ‘L’, one far to the north on the Flinders River near the Gulf of Carpentaria, which helped establish an approximate route.
The mystery of Leichhardt’s fate continued to exercise the minds of following generations of explorers: 50 years later, during David Carnegie’s 1896 expedition through the Gibson and Great Sandy Deserts, he encountered some Aborigines who had among their possessions an iron tent peg, the lid of a tin matchbox, and part of the ironwork of a saddle. Carnegie speculated these were from Leichhardt’s expedition.
In 1900 another piece of evidence provided a clue. A native stockman found a small brass plaque inscribed LUDWIG LEICHHARDT 1848, attached to a burnt-out shotgun, slung from the lower branches of a boab tree – its trunk also scratched with an ‘L’ – near Sturt Creek, close to the state border between Western Australia and the Northern Territory, a little east of the Great Sandy Desert. Taken together, the sequence of clues and markings suggest Leichhardt may have broadly retraced his first expedition, veering west then southwest across the Top End after leaving Queensland.