Northern Territory borders

Today the Northern Territory's land borders are defined to the west by the 129° east longitude (129° east) with Western Australia, to the south by the 26th parallel south latitude (26° south) with South Australia and to the east by 139° east longitude (139° east) with Queensland; however, this is not where all borders are actually marked on the ground.

The Northern Territory boundaries are shared with the West Australian border, the South Australian border, and the Queensland border.

In 1788, Governor Phillip claimed the continent of Australia as far west as the 135th meridian east longitude (135° east) in accordance with his commission. (26 January 1788 - Map)

On 16 July 1825, the western boundary of New South Wales was relocated to the line of 129° east to take in the new settlement at Melville Island. (16 July 1825 - Map). From 1825 to 1829 129° east was the NSW border.

Following the settlement of the Swan River Colony in 1829 (2 May 1829 - Map), its eastern boundary was declared to be 129° east, coinciding with the western boundary of New South Wales at the time.

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