The indigenous peoples of Australia are broadly divided into two or three groups. The largest group is the Australian Aborigines who traditionally occupied most of the Australian mainland and some offshore islands. The second group is the Torres Strait Islanders who traditionally occupied the islands of Torres Strait and part of Cape York Peninsula. Sometimes, a third group is used, separating the Tasmanian Aborigines from the mainland Aborigines. All of the indigenous peoples have dark skin, although how dark depends on where they are from.
The Australian Aborigines are further divided into about 300 separate language groups, sometimes called "nations". A map of the tribal distribution before the arrival of white settlers can be found here . In Australia, indigenous people as a broad group are usually called "Aboriginal and Torres Strait Islanders" by the government.
According to the time scale envisaged by evolutionists, the Indigenous Australians lived in Australia as far as 50 000 years ago. Evolutionists believe that genetic evidence suggests that multiple waves of people migrated into Australia over tens of thousands of years before European colonization.  Even between these "waves" the Aborigines weren't completely isolated, there was migration back and forth over the islands, allowing small levels of exchange with Melanesia. With few exceptions, complete isolation of an ethnic group is a fallacy. 
Indigenous culture has a strong focus on a form of spirituality known as the Dreaming.
Contemporary issues include health, crime, education and other social concerns.