Friedrich Wilhelm Ludwig Leichhardt, a Prussian scientist, is remembered for his long journey in 1844-5 from the Darling Downs to Port Essington, an early settlement in the far north of the Northern Territory. He proceeded up the Burdekin Valley, crossed the Dividing Range, and discovered the Lynd and Mitchell Rivers. After following the Mitchell, Leichhardt skirted the shores of the Gulf of Carpentaria. The exhausted party lost much valuable equipment at the Roper River and finally arrived at Port Essington, in December, 1845. He made the return journey by sea.

In 1846-47 Leichhardt was forced by heat and drought to turn back from an attempt to traverse Australia from east to west, but shortly afterwards again set out on an overland journey to Perth. From this expedition he did not return, and nothing certain is known of his fate.