Mantjiljarra (Manyjilyjarra) country is in the central Great Sandy Desert region of northwest Western Australia. It is north east of Telfer and includes part of the Canning Stock Route. Walmajarri borders it to the north, Warnman to the southwest with Yulparija and Nyangumarta to the west.
In 2004 there were estimated to be less than 500 speakers of the Mantjiljarra language. There may be much less than that number now as many children of Mantjiljarra people speak Martu Wangka, which combines elements of the Mantjiljarra and Kartujarra languages with influences from the Warnman, Nyiyaparli and Putijarra languages. As such, children of Mantjiljarra speakers may not speak a pure form of the language and may be unable to identify Mantjiljarra elements. Due to the development and use of Martu Wangka, Mantjiljarra is considered a highly endangered language.
Most Mantjiljarra speakers live in the communities of Punmu and Kunuwarraji in the central Great Sandy Desert region. Other people live in Parnngurr, Jigalong and Parnpajinya Communities. Many other people have intermarried and are spread across towns and communities in the northern Pilbara.