When Anglo-European Caucasian settlers first arrived in 1836 at Holdfast Bay (now Glenelg), the land was considered in the 1834 South Australia Act passed by the British Parliament and by Governor Hindmarsh as Commander in chief in his Proclamation of 1836, to be a barren wasteland. In contrast to the rest of Australia, terra nullius did not apply to the new province. The Letters Patent establishing the Province of South Australia attached to the Act acknowledged Aboriginal ownership and stated that no actions could be undertaken that would affect the rights of any Aboriginal natives of the said province to the actual occupation and enjoyment in their own persons or in the persons of their descendants of any land therein now actually occupied or enjoyed by such natives. Under the act the native inhabitants were assumed to have become British subjects. Although the patent guaranteed land rights under force of law for the indigenous inhabitants it was ignored by the South Australian Company authorities and squatters.
As with other indigenous groups in South Australia, the Ngadjuri led nomadic lives and were decimated by introduced European diseases, beginning with the spread of smallpox prior to European colonisation.
In the 1840s and 50s one Ngadjuri community was noted to wander in a wide circuit around Burra, Ulooloo, Munjibbie, and Canowie, because of the water collected by ranges there.  By the 1870s few of the Ngadjuri remained on their traditional lands and most of those left had become dependent upon the white population through land dispossession. Although there were some late attempts to arrest their decline, by the end of the nineteenth century the language group, as it had been, had ceased to exist.
Elements of the vocabulary were recorded by Samuel Le Brun, stepson of one of the Canowie Station proprietors R. Boucher James. Le Brun, who spent parts of his youth at Canowie in the late 1850s, took an interest in the Aboriginal vocabulary of the district and in 1886 was among the laymen who made submissions on this topic to a book by Edward Micklethwaite Curr (1820-1889).  Le Brun’s vocabulary has in recent times been attributed to the Nukunu people near Spencer Gulf, but he himself states it originated from ‘forty miles east of Port Pirie’, which places it near Canowie, with which he was intimately familiar, and is therefore the vocabulary of the Ngadjuri people. Their word for water, cowie or kowi, appears quite frequently as a suffix within Ngadjuri-based nomenclature of the region, such as Yarcowie, Canowie, Caltowie, Warcowie, and Booborowie.
The Ngadjuri used petroglyphs, body art, and other art forms to express their culture and beliefs. Parallel striations (lines) are a very familiar theme, but the usual panapoly of Australian indigenous art emblems (e.g. hand prints, kangaroo and emu footprints) were also used.
The Ngadjuri practiced formalised burial practices with bodies sometimes smoked or dried before burial and many buried skeletons were uncovered during the construction of the Clare Railway line. Large groups of up to a hundred men would hold mass possum hunts through the timbered hills. Although ceremonies were usually male-only private events, by the 1860s they had begun to commercialise them with the dominate capitalist culture spectators accepted and donations solicited.
Other indigenous ethnic groups in South Australia:
- Ngadjuri Walpa Juri Lands and Heritage Association (Undated). Ngadjuri. Page 73: SASOSE Council Inc. ISBN 0-646-42821-7.
- Noye, Robert J. (1980). CLARE – A District History. Hawthorndene, South Australia: Investigator Press. pp. 216–218.
- Register, 27 June 1911, p 6. Recollections of Thomas Best of Kooringa [Burra]
- Le Brun, S. 1886, ‘Port Pirie, Forty Miles East Of’, in E.M. Curr ed., The Australian Race: It’s origin, languages, customs, place of landing in Australia, and the routes by which it spread itself over that continent, vol. 2, John Ferres Government Printers, Melbourne, pp. 140-142.