The river catchment occupies an area of 6,003 square kilometres (2,318 sq mi) and is wedged between the Ord River catchment to the west and the Victoria River catchment to the east.[2] The river has a mean annual outflow of 500 gigalitres (654,000,000 cu yd).[3]
Important wetlands are found in the lower reaches of the river, forming suitable habitat for waterfowl breeding colonies and roosting sites for migratory shorebirds. Large areas of rice-grass floodplain grasslands are also found along the river.[4]
The estuary formed at the river mouth is in near pristine condition.[5] It occupies an area of 230 square kilometres (89 sq mi) of open water. It is tide dominated in nature with a tide dominated delta having multiple channels and is surrounded by an area of 55.5 square kilometres (21 sq mi) covered with mangroves.[6]
In February 2022, the Northern Territory Land Corporation released 67,500 hectares for a planned conversion of the landscape towards the cultivation of rice, cotton and various fruits like mangoes and bananas. The effects of this major project on the natural ecology and Aboriginal sacred sites are not yet known.[8]
The origin of the name is not known but it is thought to have been named for Henry Francis Keep who was a store keeper in Wyndham. The first written record of the name was in the diary of explorer and pastoralist, Michael Durack, who wrote about a "trip to Keep River" in 1894.[11]
^ abHelen Larson (4 February 1999). "Keep river Aquatic Fauna survey"(PDF). Museums and Art Galleries of the Northern Territory. Archived from the original(PDF) on 6 April 2015. Retrieved 3 May 2015.
^"Duulngari". AusAnthrop Australian Aboriginal tribal database. Ausanthrop. 2005. Archived from the original on 27 September 2015. Retrieved 3 May 2015.
^"Miriwung". AusAnthrop Australian Aboriginal tribal database. Ausanthrop. 2005. Archived from the original on 11 September 2015. Retrieved 3 May 2015.