Mackenzie Valley Pipeline, proposed pipeline for the transport of natural gas and later oil from the Arctic Ocean to Alberta. The proposal of a pipeline corridor from the North was put forward by the federal government in the 1970 Pipeline Guidelines and provoked a spate of engineering and environmental studies, public-policy reviews and economic analyses unequalled in Canadian history.

Detailed proposals were promulgated by 2 consortiums. Canadian Arctic Gas Pipeline Ltd, composed of 27 Canadian and American producers (including Exxon, Gulf, Shell and TransCanada PipeLines), proposed a route from the Prudhoe fields in Alaska, across the northern Yukon to the Mackenzie Delta and then south to Alberta. Foothills Pipe Lines Ltd, formed by Alberta Gas Trunk Line [NOVA] and Westcoast Transmission, proposed a shorter route from the Mackenzie Delta to Alberta. The Arctic Gas pipeline would have been the longest in the world (3860 km) and the greatest construction enterprise ever undertaken. In either case, the engineering problems of building a pipeline over permafrost were monumental (both proposals entailed refrigerating the gas) and the impact on the North would have been significant.

A federal royal commission, led by Judge Thomas Berger, was appointed in March 1974 to consider the proposals and their social and economic impact on the North. The commissioners held community hearings across the North, beginning in 1975 and ending November 1976, dealing with the concerns of native people and environmentalists. The commission's report, issued April 1977, concluded that a pipeline from the Mackenzie Delta down the Mackenzie Valley to Alberta was feasible, but should proceed only after further study and after settlement of native land claims; it recommended, successfully, a 10-year moratorium. However, the commission was adamantly opposed to the building of a line across the delicate environment of the northern Yukon. Amid controversy and uncertain economic conditions, both plans were shelved. The commission itself became a cause célèbre because of its broad interpretation of its mandate and its illumination of the complex problems facing northern development.