Much of the landscape of the reserve is rugged; it contains a section of the Wunaamin-Miliwundi Ranges and the upper catchment of the Fitzroy River, as well as the mesas of the Baulk Face Range and Fitzroy Bluff. Tributaries of the Fitzroy River flow through vertically walled gorges, such as Dimond Gorge. Lake Gladstone, the largest wetland in the Kimberley, lies in the north-west part of the reserve. Vegetation is predominantly various forms of tropical savannawoodland and grassland regulated by frequent wildfires. Fragments of rainforest communities such as Livistona palm forests may be found in gullies and other areas protected from fires.[3][4]
The climate is tropical and monsoonal with distinct wet (November–April) and dry (May–October) seasons. Average annual rainfall is about 700 mm.[5]
Mornington Sanctuary is remote. Road access to the Wilderness Camp is by 4WD vehicles only, via the Gibb River Road and the 90 km no-through Mornington Road, and may be closed during the wet season. Driving distances and estimated times are: