511 is the leading decision of the Supreme Court of Canada on the Crown duty to consult Aboriginal groups prior to exploiting lands to which they may have claims.

In 1961, the provincial government of British Columbia issued a "Tree Farm Licence" (TFL 39) over an area of land to which the Haida Nation claimed title.

[citation needed] The chambers judge found that the Crown was under a moral – but not legal – duty to negotiate with the Haida Nation.

The British Columbia Court of Appeal reversed this decision, deciding that both the Crown and Weyerhauser Co. are under legal obligations to consult with Aboriginal groups whose interests may be affected.

Chief Justice McLachlin, writing for a unanimous court, found that the Crown has a "duty to consult with Aboriginal peoples and accommodate their interests".