The federal government says portions of unused land that Quebec farmers were forced to sell decades ago for the failed Mirabel airport will be returned.

The Canadian government says 300 hectares of land it expropriated in the 1960s for construction of the airport will be sold back to original owners or their descendants.

The expropriations affected approximately 3,000 families.

Ottawa sold back a large portion of the land in the 1980s, and in 2006 it began returning remaining land outside the airport zone. But 300 hectares of land inaccessible by road were still being held -- until now.

The new sale ends a decades-long territory dispute over expropriated land outside the airport zone.

In 1969, the federal government bought 38,800 hectares of Quebec farmland with the promise of a modern airport that Ottawa said would become a hub for world travel and create hundreds of jobs.

The airport -- located 39 kilometres northwest of Montreal -- opened in 1975 as the largest airport in the world in surface size and the most expensive airport built in Canadian history.

The Mirabel airport had better facilities than the then-Dorval Airport, but it lacked convenient highway and transit links to Montreal and quickly became unpopular among passengers.

Passenger flights at Mirabel airport stopped in 2004 and in 2014, its abandoned terminal was demolished after being found too costly to repurpose.

The airport still serves cargo airlines.

With files from The Canadian Press