On 14 February 1842 Leichhardt arrived in Sydney, Australia.
His aim was to explore inland Australia and he was hopeful of a government appointment in his fields of interest.
In September 1842 Leichhardt went to the Hunter River valley north of Sydney to study the geology, flora and fauna of the region, and to observe farming methods.
He then set out on his own on a specimen-collecting journey that took him from Newcastle, New South Wales, to Moreton Bay in Queensland.

After returning to Sydney early in 1844, Leichhardt hoped to take part in a proposed government-sponsored expedition from Moreton Bay to Port Essington (300 km north of Darwin).
When plans for this expedition fell through Leichhardt decided to mount the expedition himself, accompanied by volunteers  and supported by private funding.
His party left Sydney in August 1844 to sail to Moreton Bay, where four more joined the group.
The expedition departed on 1 October 1844 from Jimbour Homestead, the farthest outpost of settlement on the Queensland Darling Downs.
During this trip, Leichhardt named Seven Emu Creek, after shooting a mob of emus nearby, a name later taken on by a large cattle station still in existence, Seven Emu Station.

After a nearly 4,800 kilometres (3,000 miles) overland journey, and having long been given up for dead, Leichhardt arrived in Port Essington on 17 December 1845.
He returned to Sydney by boat, arriving on 25 March 1846 to a hero's welcome.
The Journal of an Overland Expedition in Australia, from Moreton Bay to Port Essington, a Distance of Upwards of 3000 miles, During the Years 1844 and 1845 by Leichhardt describes this expedition.

A memorial to John Gilbert, one of Leichhardt's companions on this journey, can be found on the north wall of St James' Church, Sydney.
Under the title Dulce et Docorum Est Pro Scientia Mori (a variation on the more commonly seen Dulce et decorum est pro patria mori) the inscription on the monument, which was "erected by the colonists of New South Wales" reads: "in memory of John Gilbert, Ornithologist, who was speared by the blacks on 29 June 1845 during the first overland expedition to Port Essington by Dr Ludwig Leichhardt and his intrepid companions".
There is also a memorial to Gilbert at Gilbert's Lookout at Taroom.

Leichhardt's second expedition, undertaken with a government grant and substantial private subscriptions, started in December 1846.
It was supposed to take him from the Darling Downs to the west coast of Australia and ultimately to the Swan River and Perth.
However, after covering only 800 km the expedition team was forced to return in June 1847 due to heavy rain, malarial fever and famine.
After recovering from malaria Leichhardt spent six weeks in 1847 examining the course of the Condamine River, southern Queensland, and the country between the route of another expedition led by Sir Thomas Mitchell in 1846 and his own route, covering nearly 1,000 km.

In April 1847 Leichhardt shared the annual prize of the Paris Geographical Society, for the most important geographic discovery with the French explorer Charles-Xavier Rochet d'Héricourt.
Soon afterward, on 24 May, the Royal Geographical Society, London, awarded Leichhardt its Patron's Medal as recognition of 'the increased knowledge of the great continent of Australia' gained by his Moreton Bay-Port Essington journey.
Leichhardt himself never saw these medals but was aware he had been awarded them.
In one of his last known letters he wrote:
I've had the pleasure of hearing that the geographical society in London has awarded me one of its medals, and that the Parisian geographical society has conferred a similar honour upon me.
Naturally I'm very pleased to think that such discerning authorities consider me worthy of such honour; but whatever I have done has never been for honour.
I have worked for the sake of science, and for nothing else.

In 2012 the National Museum of Australia purchased the medal awarded to Leichhardt by London's Royal Geographical Society in 1847.
It came directly from descendants of the Leichhardt family in Mexico
On 14 February 1842 Leichhardt arrived in Sydney, Australia. His aim was to explore inland Australia and he was hopeful of a government appointment in his fields of interest. In September 1842 Leichhardt went to the Hunter River valley north of Sydney to study the geology, flora and fauna of the region, and to observe farming methods. He then set out on his own on a specimen-collecting journey that took him from Newcastle, New South Wales, to Moreton Bay in Queensland.
After returning to Sydney early in 1844, Leichhardt hoped to take part in a proposed government-sponsored expedition from Moreton Bay to Port Essington (300 km north of Darwin). When plans for this expedition fell through Leichhardt decided to mount the expedition himself, accompanied by volunteers  and supported by private funding. His party left Sydney in August 1844 to sail to Moreton Bay, where four more joined the group. The expedition departed on 1 October 1844 from Jimbour Homestead, the farthest outpost of settlement on the Queensland Darling Downs. During this trip, Leichhardt named Seven Emu Creek, after shooting a mob of emus nearby, a name later taken on by a large cattle station still in existence, Seven Emu Station.
After a nearly 4,800 kilometres (3,000 miles) overland journey, and having long been given up for dead, Leichhardt arrived in Port Essington on 17 December 1845. He returned to Sydney by boat, arriving on 25 March 1846 to a hero's welcome. The Journal of an Overland Expedition in Australia, from Moreton Bay to Port Essington, a Distance of Upwards of 3000 miles, During the Years 1844 and 1845 by Leichhardt describes this expedition.
A memorial to John Gilbert, one of Leichhardt's companions on this journey, can be found on the north wall of St James' Church, Sydney. Under the title Dulce et Docorum Est Pro Scientia Mori (a variation on the more commonly seen Dulce et decorum est pro patria mori) the inscription on the monument, which was "erected by the colonists of New South Wales" reads: "in memory of John Gilbert, Ornithologist, who was speared by the blacks on 29 June 1845 during the first overland expedition to Port Essington by Dr Ludwig Leichhardt and his intrepid companions". There is also a memorial to Gilbert at Gilbert's Lookout at Taroom.
Leichhardt's second expedition, undertaken with a government grant and substantial private subscriptions, started in December 1846. It was supposed to take him from the Darling Downs to the west coast of Australia and ultimately to the Swan River and Perth. However, after covering only 800 km the expedition team was forced to return in June 1847 due to heavy rain, malarial fever and famine. After recovering from malaria Leichhardt spent six weeks in 1847 examining the course of the Condamine River, southern Queensland, and the country between the route of another expedition led by Sir Thomas Mitchell in 1846 and his own route, covering nearly 1,000 km.
In April 1847 Leichhardt shared the annual prize of the Paris Geographical Society, for the most important geographic discovery with the French explorer Charles-Xavier Rochet d'Héricourt. Soon afterward, on 24 May, the Royal Geographical Society, London, awarded Leichhardt its Patron's Medal as recognition of 'the increased knowledge of the great continent of Australia' gained by his Moreton Bay-Port Essington journey. Leichhardt himself never saw these medals but was aware he had been awarded them. In one of his last known letters he wrote:
I've had the pleasure of hearing that the geographical society in London has awarded me one of its medals, and that the Parisian geographical society has conferred a similar honour upon me. Naturally I'm very pleased to think that such discerning authorities consider me worthy of such honour; but whatever I have done has never been for honour. I have worked for the sake of science, and for nothing else.
In 2012 the National Museum of Australia purchased the medal awarded to Leichhardt by London's Royal Geographical Society in 1847. It came directly from descendants of the Leichhardt family in Mexico
Ludwig Leichhardt