Canada's Supreme Court has recognised native groups' rights over a large swathe of land in western British Columbia province for the first time.
The landmark ruling in favour of the semi-nomadic Tsilhqot'in people, numbering about 3,000, could have an impact on similar Native American claims currently pending in court.
It could also impact on mining, forestry and other projects exploiting raw materials across vast portions of Canada.
In 2012, a British Columbia appeals court had refused to recognise the Tsilhqot'in people's ancestral rights over the land in the centre of the province.
It said that they needed to identify the "specific sites" their ancestors had used when the Europeans arrived, rather than lay claim to the broad area.
The Supreme Court threw out that decision, stressing that "occupation sufficient to ground Aboriginal title is not confined to specific sites of settlement but extends to tracts of land that were regularly used for hunting, fishing or otherwise exploiting resources and over which the group exercised effective control at the time of assertion of European sovereignty."
The high court's ruling ends a court saga that dragged on for decades, starting when the provincial government granted a commercial forestry permit on land that the Tsilhqot'in people considered part of their ancestral territory.
Both the provincial government and the federal government in Ottawa had contested the Tsilhqot'in people's claims, but the high court said British Columbia had failed to fulfill its constitutional duty to consult with the aboriginal community.
The Supreme Court's ruling does not grant absolute rights for the indigenous group over its ancestral land.
However the province can no longer authorise projects on the territory without the aboriginal people's consent, unless it proves a real and pressing public objective, and appropriately compensates the Tsilhqot'in.
"This is truly a landmark decision that compels us all to embark on a new course," said Assembly of First Nations spokesman Ghislain Picard, the regional chief for Quebec and Labrador.
"The court has clearly sent a message that the crown must take aboriginal title seriously and reconcile with First Nations honourably.
"This decision will no doubt go down in history as one of the most important and far reaching ever rendered by the Supreme Court of Canada."