In Canadian law all lands are subject to the Crown, and this has been true since Britain acquired much of Eastern Canada from France by the Treaty of Paris (1763). However, the British and Canadian authorities recognized that indigenous peoples already on the lands had a prior claim, Aboriginal title, which was not extinguished by the arrival of the Europeans. This is in direct contrast to the situation in Australia where the continent was declared Terra nullius, or vacant land, and was seized from Aboriginal peoples without compensation. In consequence, all of Canada, save a section of southern Quebec exempted by the Royal Proclamation of 1763, is subject to Aboriginal title. Native groups historically negotiated treaties in which they traded tenure to the land for annuities and certain legal exemptions and privileges. Most of Western Canada was secured in this way by the government via the Numbered Treaties of 1871 to 1921. Those Native groups, which never signed treaties or are dissatisfied with the execution of those treaties can lodge Aboriginal land claims against the government.
Aboriginal title has been recognized existed in Canada since the Privy Council, in St. Catherines Milling v. The Queen (1888), characterized it as a personal usufruct at the pleasure of the Queen. This case did not involve indigenous parties, but rather was a lumber dispute between the provincial government of Ontario and the federal government of Canada. St. Catherines was decided in the wake of the Indian Act (1876), which laid out an assimilationist policy towards the aboriginal peoples in Canada (First Nations, Inuit, and Métis), allowed provinces to abrogate treaties (until 1951).
St. Catherines was more or less the prevailing law until Calder v. British Columbia (Attorney General) (1973). All seven of the judges in Calder agreed that the claimed aboriginal title existed, and did not solely depend upon the Royal Proclamation of 1763. Six of the judges split 3–3 on the question of whether aboriginal title had been extinguished. The Nisga'a did not prevail because the seventh justice, Pigeon J, found that the Court did not have jurisdiction to make a declaration in favour of the Nisga'a in the absence of a fiat of the Lieutenant-Governor of B.C. permitting suit against the provincial government.
Section 91(24) of the Constitution Act, 1867 gives the federal government exclusive jurisdiction over First Nations, and thus the exclusive ability to extinguish aboriginal title. Section Thirty-five of the Constitution Act, 1982 explicitly recognized and preserved aboriginal rights. R. v. Guerin (1982), the first Supreme Court of Canada decision handed down after the Constitution Act 1982, declared that aboriginal title was sui generis and that the federal government has a fiduciary duty to preserve it. R. v. Simon (1985) overruled R. v. Syliboy (1929) which had held that aboriginal peoples had no capacity to enter into treaties, and thus that the Numbered Treaties were void. A variety of non-land rights cases, anchored on the Constitution Act 1982, have also been influential.
Guerin v. The Queen  2 S.C.R. 335 was a landmark Supreme Court of Canada decision on aboriginal rights where the Court first stated that the government has a fiduciary duty towards the First Nations of Canada and established aboriginal title to be a sui generis right.
The Musqueam Indian band held roughly 416 acres (1.7 km2) of prime land in the Vancouver area. In 1958, the federal government, on behalf of the band, made a deal with the Shaughnessy Heights Golf Club to lease 162 acres (0.7 km2) of the land in order to build a golf club. However, the actual terms of the agreement between the government and the club were not those that were told to the band.
In 1970, the band discovered the true terms and protested on the basis that the government had a duty to properly explain the full extent of the deal.
At trial, the court held that the Crown had breached their trust with the band and awarded the Musqueam ten million dollars. This ruling was overturned by the Federal Court of Appeal. The matter was then considered by the Supreme Court of Canada.
Dickson J., with Beetz, Chouinard, and Lamer concurring, held that the nature of aboriginal title imposes an enforceable fiduciary duty upon the Crown. Dickson described the nature of aboriginal title as a sui generis right that has no equivalent. It is an inherent right that existed prior to the Royal Proclamation of 1763 and is founded in historical occupation. This special right means that title to aboriginal land can only be alienable to the Crown and the Crown can only use it in the interests of the aboriginals.
Delgamuukw v. British Columbia (1997) laid down the essentials of the current test to prove aboriginal title: "in order to make out a claim for aboriginal title, the aboriginal group asserting title must satisfy the following criteria: (i) the land must have been occupied prior to sovereignty, (ii) if present occupation is relied on as proof of occupation pre-sovereignty, there must be a continuity between present and pre-sovereignty occupation, and (iii) at sovereignty, that occupation must have been exclusive."
Subsequent decisions have drawn on the fiduciary duty to limit the ways in which the Crown can extinguish aboriginal title, and to require prior consultation where the government has knowledge of a credible, but yet unproven, claim to aboriginal title.