Map of Australia with relief shown by hachures. Boundaries mark the Northern Territory of South Australia and South Australia as one state.

The unnamed region of New South Wales between the eastern border of Western Australia and western border of Queensland was annexed to South Australia in 1863. Western Australia's eastern border was delineated in 1829 when that colony was established. South Australia's northern border was defined in 1836 and the western border of Queensland was formalised by the early 1860s.

In 1862 John McDouall Stuart successfully crossed the continent from Adelaide in the south to the northern coast, travelling through the northern lands. The South Australian government made claim to the territory, and on 6 July 1863 the British Government issued Letters Patent annexing the Northern Territory to the southern colony.

Permanent settlement was established from 1869 at Port Darwin (several earlier British settlements in Northern Australia had been abandoned). In February 1869 Surveyor-General of South Australia, George Goyder, founded Palmerston, later known as Darwin. In the early 1870s the construction of the Overland Telegraph, following the route forged by explorer Stuart, furthered more exploration of the Territory and opened up communications between Australia and overseas. In 1911 the Northern Territory was transferred to direct control by the Commonwealth of Australia.

Donovan, PF. A Land Full of Possibilities: A History of South Australia's Northern Territory, St. Lucia, Qld.: University of Queensland Press, 1981

Powell, Alan. Far country: a short history of the Northern Territory, Melbourne: Melbourne University Press, 1996

Documenting a democracy See: Places: Northern Territory; Timeline