Formed by the confluence of the Waterhouse River and Roper Creek, the Roper River rises east of Mataranka in the Elsey National Park and flows generally east for over 400 km (250 mi) to meet the sea in Limmen Bight on the Gulf of Carpentaria.

Annual flooding is essential for the health of its nationally significant coastal wetlands and seagrass beds of Limmen Bight, that are habitat for turtles and dugongs, as well as the barramundi, prawns and crabs that are fished recreationally and commercially.

[8] The traditional owners of the Roper River are the Ngalakgan, Alawa, Mangarrayi, Ngandi, Marra, Warndarrang, Nunggubuyu, Ritharrngu-Wagilak and Rembarrnga peoples.

[8] The first European to explore the Roper River was Ludwig Leichhardt in 1845 as he made his way from Moreton Bay to Port Essington.

[11] In 1988, control of the town was handed to the Yugul Mangi Community Government Council, and the township was renamed Ngukurr.