The Northern Territory (abbreviated as NT; known formally as the Northern Territory of Australia and informally as the Territory) is an Australian internal territory in the central and central-northern regions of Australia. The Northern Territory shares its borders with Western Australia to the west (129th meridian east), South Australia to the south (26th parallel south), and Queensland to the east (138th meridian east). To the north, the Northern Territory looks out to the Timor Sea, the Arafura Sea and the Gulf of Carpentaria, including Western New Guinea and various other islands of the Indonesian archipelago.