The meridian 138° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Pacific Ocean, Australasia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole.
The 138th meridian east forms a great circle with the 42nd meridian west.
In Australia, the border between the Northern Territory and Queensland approximates the meridian. The border runs north from Poeppel Corner at a bearing of 359° 59' 30", reaching the Gulf of Carpentaria several hundred meters west of the meridian.[1]