In Norman Tindale's estimation the Mariu's territory covered some 1,800 square miles (4,700 km2) in the area south of where the Victoria River enters the Joseph Bonaparte Gulf. The Bullo River also formed part of their land.
In 1900, R. H. Mathews presented a paper attributing to the Mariu, together with other "large and important tribes", from both Western Australia and the Northern Territory, such as the Gija, Perrakee, Gooniyandi, Nyigina, Bunuba, Djaru and Walmadjari an 8 section marriage system among clans, which he illustrated in the following general table.
- K38 Mariung at the Australian Indigenous Languages Database, Australian Institute of Aboriginal and Torres Strait Islander Studies
- Tindale 1974, p. 231.
- Mathews 1900, p. 186.
- Mathews, R.H. (January 1900). "Divisions of some West Australian tribes". American Anthropologist. 2 (1): 185–187. JSTOR 658875.
- Tindale, Norman Barnett (1974). "Mariu (NT)". Aboriginal Tribes of Australia: Their Terrain, Environmental Controls, Distribution, Limits, and Proper Names. Australian National University.