Thomas MacDonald, director of the U.S. Bureau of Public Roads, dreamed of an international highway spanning the United States and Canada.

However, the Canadian government perceived no value in putting up the required funds to build the road, since the only part of Canada that would benefit was not more than a few thousand people in Yukon.

Roosevelt became the first American to publicly discuss the military benefits of a highway in an August speech in Chautauqua, New York.

Roosevelt remained a supporter of the highway, telling Cordell Hull in August 1937 that he wanted a road built as soon as possible.

[5] The December 7, 1941 attack on Pearl Harbor and beginning of the Pacific Theater in World War II, coupled with Japanese threats to the west coast of North America and the Aleutian Islands, changed the priorities for both nations.

On February 6, 1942, the construction of the Alaska Highway was approved by the United States Army and the project received the authorization from the U.S. Congress and Roosevelt to proceed five days later.

It proved unimportant for the military because 99 percent of the supplies to Alaska during the war were sent by sea from San Francisco, Seattle, and Prince Rupert.

[7][better source needed] The Americans preferred Route A which, starting at Prince George, went northwest to Hazelton, along the Stikine River, by Atlin, Teslin and Tagish Lakes, and from Whitehorse, Yukon, to Fairbanks, Alaska, via the Tanana Valley.

However, the route was vulnerable to possible enemy attack from the sea, experienced steep grades and heavy snowfall, and had no airbases along the way.

It was far enough inland from enemy planes and it linked the airfields of the Northwest Staging Route that conveyed lend-lease aircraft from the United States to the Soviet Union.

There was also a railhead at Dawson Creek, British Columbia, and a winter trail from there to Fort Nelson, 300 miles (480 km) to the northwest.

[8] The road was originally built mostly by the U.S. Army Corps of Engineers as a supply route during World War II.

In 1942, the Army Corps of Engineers assigned more than 10,000 men, about a third of whom were black soldiers, members of three newly formed African-American segregated regiments.

The Army commandeered equipment of all kinds, including local riverboats, railway locomotives, and housing originally meant for use in southern California.

Pincers on Japan and Look to the North, both 1944 productions, were National Film Board of Canada documentaries that depicted the construction of the Alaska Highway.

The Alaska Highway was built for military purposes and its route was not ideal for postwar development of northern Canada.

[19] Rerouting in Canada has shortened the highway by about 35 miles (56 km) since 1947, mostly by eliminating winding sections and sometimes by bypassing residential areas.

Although Champagne, Yukon was bypassed in 2002, the old highway is still completely in service for that community until a new direct access road is built.

Under Shakwak, U.S. federal highway money is spent for work done by Canadian contractors who win tenders issued by the Yukon government.

The latest BC recalibration was carried out in 1990; using its end-point at the border at Historic Mile 630, the Yukon government has recalibrated in three stages: in 2002, from Mile 630 to the west end of the Champagne revision; in fall 2005, to a point just at the southeast shore of Kluane Lake, and in fall 2008, to the border with Alaska.

and Yukon sections of the highway, installed in 1992, that note specific locations, although the posts no longer represent accurate driving distance.

There are 18 interpretive panels in B.C., 14 in Yukon and 5 in Alaska which give detailed text information at a turn-off parking area.

The section of highway covered by the 1990 recalibration has since been rendered shorter by further realignments, such as near Summit Pass and between Muncho Lake and Iron Creek.

Old kilometre posts, based on the historic miles, remained on the highway, after the first two recalibrations, from those points around Kluane Lake to the Alaska border.

The Alaska portion of the highway is still marked by mileposts at 1-mile (1.6 km) intervals, although they no longer represent accurate driving distance, due to reconstruction.

[22] Certain prior editions of United States Geological Survey topographic maps, mostly published during the 1950s, bore the US 97 highway shield along or near portions of the current AK-2.

At Fort Nelson, the road turns west and crosses the Rocky Mountains, before resuming a westward course at Coal River.

After passing the south end of Kluane Lake, the highway follows a north-northwest course to the Alaska border, then northwest to the terminus at Delta Junction.