It was set up to detect incoming bombers of the Soviet Union during the Cold War, and provide early warning of any sea-and-land invasion.

The DEW Line was proposed as a solution to both of these problems, using conventional radar systems that could both detect and characterise an attack, while being located far to the north where they would offer hours of advance warning.

This would not only provide ample time for the defences to prepare, but also allow the Strategic Air Command to get its active aircraft airborne long before Soviet bombers could reach their targets.

In 1985, as part of the "Shamrock Summit", the United States and Canada agreed to transition DEW to the new North Warning System (NWS).

The DEW Line was built during the Cold War to give early warning of a Soviet nuclear strike, to allow time for United States bombers to get off the ground and land-based intercontinental ballistic missile (ICBMs) to be launched, to reduce the chances that a preemptive strike could destroy the United States' strategic nuclear forces.

A successful combination of scientific design and logistical planning of the late 1950s, the DEW Line consisted of a string of continental defence radar installations, ultimately stretching from Alaska to Greenland.

The subject of the study was the vulnerability of the United States and Canada to aerial bombing attacks, and its concluding recommendation was that a distant early warning line of search radar stations be built across the Arctic region of the North American continent as rapidly as possible.

Material converted from Navy use included 1,200 tons of supplies, with many Caterpillar D8 tractors, heavy duty cranes, diesel generators, and radio equipment.

These were completely equipped for camp operations and were of various types - Cook, Mess, Bunk, Power Plant, Water, Shop, Storage, Utility, Steam Point, etc.

[5] With the experimental phase completed successfully, the Air Forces asked the Western Electric Company to proceed as rapidly as possible with the construction of the entire DEW Line.

They covered vast distances by airplanes, snowmobiles, and dog sleds, working in blinding snowstorms with temperatures so low that ordinary thermometers could not measure them.

[5] From a standing start in December 1954, many thousands of skilled workers were recruited, transported to the polar regions, housed, fed, and supplied with tools, machines, and materials to construct physical facilities – buildings, roads, tanks, towers, antennas, airfields, and hangars – in some of the most hostile and isolated environments in North America.

[8] Later, military and civilian airlifts, huge sealifts during the short summers, barges contributed to the distribution of vast cargoes along the length of the Line to build the permanent settlements needed at each site.

They went with the convoys of United States Navy ships and they raced time during the few weeks the ice was open to land supplies at dozens of spots on the shores of the Arctic Ocean during the summers of 1955, 1956, and 1957.

In all, over 7,000 bulldozer operators, carpenters, masons, plumbers, welders, electricians, and other tradesmen from the United States and southern Canada worked on the project.

Concrete was poured in the middle of Arctic winters, buildings were constructed, electrical service, heating, and fresh water were provided, huge steel antenna towers were erected, airstrips and hangars were built, putting it all together in darkness, blizzards, and subzero temperatures.

Finally all was ready, and on 15 April 1957 – just two years and eight months after the decision to build the Distant Early Warning Line was made – Western Electric turned over to the Air Force on schedule a complete, operating radar system across the top of North America, with its own communications network.

All of the installations flew both the Canadian and United States flags until they were deactivated as DEW sites and sole jurisdiction was given to the Government of Canada as part of the North Warning System in the late 1980s and early 1990s.

[9] Average power output 400 watts Modifications to each operating radar station occurred during the construction phase of the DEW Line system.

The "gaps" between the stations were watched by the directional AN/FPS-23 doppler radar systems, similar to those pioneered only a few years earlier on the Mid-Canada Line.

It did so by providing Distant Early Warning of an inbound aerial invasion force, which would have to appear at the far north hours ahead of any warhead launches in order to be coordinated well enough to prevent MAD.

Because the advent of ICBMs created another attack scenario that the DEW Line could not defend against, in 1958 the United States Federal Government authorized construction of the Ballistic Missile Early Warning System (BMEWS), at a reported cost of $28 billion.

This upgrading was completed in 1990, and with the end of the Cold War and dissolution of the Soviet Union, the United States withdrew all of its personnel and relinquished full operation of the Canadian stations to Canada.

[citation needed] The United States retained responsibility and all operational costs for North Warning System stations located in Alaska and Greenland.

American investment in building and operating the DEW Line system declined as the ICBM threat refocused priorities, but Canada did not fill the void with commensurate additional funding.

In Canada, the DEW line increased connections between the populous south and the remote High Arctic, helping to bring Inuit more thoroughly into the Canadian polity.

[20] In assessing the cleanup, new research suggests that off-road vehicles damaged vegetation and organic matter, resulting in the melting of the permafrost, a key component to the hydrological systems of the areas.

[21] The DEW Line has also been linked to depleted fish stocks and carelessness in agitating local animals such as the caribou, as well as non-seasonal hunting.

[21] The DEW line was supplemented by the Contiguous Radar Coverage System, which included two "barrier" forces in the Atlantic and the Pacific oceans which were operated by the United States Navy from 1956 to 1965.

Their objective was to extend early warning coverage against surprise Soviet bomber and missile attack as an extension of the DEW Line.