In 1848 Leichhardt again set out from the Condamine River to reach the Swan River.
The expedition consisted of Leichhardt, four Europeans, two Aboriginal guides, seven horses, 20 mules and 50 bullocks.
The Europeans were Adolph Classen, Arthur Hentig, Donald Stuart and Thomas Hands, a ticket of leave holder who replaced Kelly at Henry Stuart Russell's Cecil Plains station.
The Aboriginal guides were Wommai and Billy Bombat, from Port Stephens.

The party was last seen on 3 April 1848 at Allan Macpherson's station, Cogoon, on the Darling Downs.
Leichhardt's disappearance after moving inland, although investigated by many, remains a mystery.
The expedition had been expected to take two to three years, but after no sign or word was received from Leichhardt it was assumed that he and the others in the party had died.
The latest evidence suggests that they may have perished somewhere in the Great Sandy Desert of the Australian interior.

Four years after Leichhardt's disappearance, the Government of New South Wales sent out a search expedition under Hovenden Hely.
The expedition found nothing but a single campsite with a tree marked "L" over "XVA".
In 1858 another search expedition was sent out, this time under Augustus Gregory.
On 21 April near what is now Blackall, beside the Barcoo River, this expedition found a tree marked "L".

In 1864 Duncan McIntyre discovered two trees marked with "L" on the Flinders River near the Gulf of Carpentaria.
After his return to Victoria McIntyre telegraphed the Royal Society on 15 December 1864 that he had found "two trees marked L about 15 years old".
He was subsequently appointed leader of a search expedition, but found no further trace of Leichhardt.

In 1869 the Government of Western Australia heard rumours of a place where the remains of horses and men killed by indigenous Australians could be seen.
A search expedition was sent out under John Forrest, but nothing was found, and it was decided that the story might refer to the bones of horses left for dead at Poison Rock during Robert Austin's expedition of 1854.

The mystery of Leichhardt's fate remained in the minds of explorers for many years.
During David Carnegie's expedition through the Gibson and Great Sandy Deserts in 1896 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 that these were from Leichhardt's expedition.
Except for a small brass plate that was found in 1900 bearing Leichhardt's name, "no artefacts with corroborated provenance have been able to shed light on Leichhardt's final expedition".

In 1975, a ranger named Zac Mathias exhibited photographs in Darwin of aboriginal cave paintings that showed white men with an animal.
In 1848 Leichhardt again set out from the Condamine River to reach the Swan River. The expedition consisted of Leichhardt, four Europeans, two Aboriginal guides, seven horses, 20 mules and 50 bullocks. The Europeans were Adolph Classen, Arthur Hentig, Donald Stuart and Thomas Hands, a ticket of leave holder who replaced Kelly at Henry Stuart Russell's Cecil Plains station. The Aboriginal guides were Wommai and Billy Bombat, from Port Stephens.
The party was last seen on 3 April 1848 at Allan Macpherson's station, Cogoon, on the Darling Downs. Leichhardt's disappearance after moving inland, although investigated by many, remains a mystery. The expedition had been expected to take two to three years, but after no sign or word was received from Leichhardt it was assumed that he and the others in the party had died. The latest evidence suggests that they may have perished somewhere in the Great Sandy Desert of the Australian interior.
Four years after Leichhardt's disappearance, the Government of New South Wales sent out a search expedition under Hovenden Hely. The expedition found nothing but a single campsite with a tree marked "L" over "XVA". In 1858 another search expedition was sent out, this time under Augustus Gregory. On 21 April near what is now Blackall, beside the Barcoo River, this expedition found a tree marked "L".
In 1864 Duncan McIntyre discovered two trees marked with "L" on the Flinders River near the Gulf of Carpentaria. After his return to Victoria McIntyre telegraphed the Royal Society on 15 December 1864 that he had found "two trees marked L about 15 years old". He was subsequently appointed leader of a search expedition, but found no further trace of Leichhardt.
In 1869 the Government of Western Australia heard rumours of a place where the remains of horses and men killed by indigenous Australians could be seen. A search expedition was sent out under John Forrest, but nothing was found, and it was decided that the story might refer to the bones of horses left for dead at Poison Rock during Robert Austin's expedition of 1854.
The mystery of Leichhardt's fate remained in the minds of explorers for many years. During David Carnegie's expedition through the Gibson and Great Sandy Deserts in 1896 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 that these were from Leichhardt's expedition. Except for a small brass plate that was found in 1900 bearing Leichhardt's name, "no artefacts with corroborated provenance have been able to shed light on Leichhardt's final expedition".
In 1975, a ranger named Zac Mathias exhibited photographs in Darwin of aboriginal cave paintings that showed white men with an animal.
Ludwig Leichhardt