Whadjuk, also called Wadjuk, Whajook, Wajuk and Wadjug, according to Norman Tindale of the Museum, is the name of the Noongar dialectical group inhabiting the Western Australian region of the Perth bioregion of the Swan Coastal Plain, and extending below Walyunga into the surrounding Jarrah Forests according to Tindale. The etymology is unknown but it has been suggested that it may come from Wirtj, meaning "those who went before" (i.e. ancestral ones), and implied that Tindale's informants considered all Whadjuk people were dead. There were a number of causes of death. In addition to white killings and massacres in Fremantle and elsewhere, the arrival of Europeans saw many deaths from diseases to which Aboriginal people had no resistance. These were interpreted as sorcery within traditional culture and led to "pay-back" vendettas, which increased mortality of those in closest contact with Europeans.
Although it does not appear that Aboriginal people occupied bounded territories in the same way as did Europeans, Tindale's boundaries of this region are the watershed division north of Yanchep between the Swan-Avon and the Moore Rivers, in the north, the Walyunga-Gidgegannup (from Gidgie = spear, gan- = make, -up = place) region to the north east, the Canning River catchment to the south east, to the coast at Port Kennedy. The boundaries as outlined by Tindale are still disputed by elders in the community today. Within this region is Cottesloe, Karrakatta, Bassendean sand dune systems and intervening wetlands, extending out to the fertile loams of the Guildford area, and the Darling Scarp to the edge of the Wandoo region, inhabited by the Balardong people to the east. To the north, according to Tindale is the land of the Juat, Yued or Yuat, and to the south, the Pindjarup or Pinjareb peoples.