It has an area of 1.35 million square kilometres, equal to the combined areas of France, Spain and Italy, and a coastline of 6200km. The coastline is generally flat, with a backing of swamps, mangroves and mudflats, rising to a plateau no higher than 450m. In central Australia, the Territory is crossed by the east-west ridges of the Macdonnell Ranges, which reach heights of more than 600m. The northern quarter, known colloquially as the Top End, is a distinct region of savannah woodlands and pockets of rainforest. In the north-east, the Arnhem Land plateau rises abruptly from the plain and continues to the coast of the Gulf of Carpentaria.
Inland rivers are dry most of the year and their sporadic flow is lost in the Simpson Desert .