The original agreement between Canada and the United States regarding construction of the highway stipulated that its Canadian portion be turned over to Canada six months after the end of the war. This took place on April 1, 1946 when the U.S. Army transferred control of the road through Yukon and British Columbia to the Canadian Army, Northwest Highway System. The Alaskan section was completely paved during the 1960s; largely gravel even in 1981, the Canadian portion of the Alaska Highway is now completely paved, mostly with bituminous surface treatment.
The Milepost, an extensive guide book to the Alaska Highway and other highways in Alaska and Northwest Canada, was first published in 1949 and continues to be published annually as the foremost guide to traveling the highway.
The British Columbia government owns the first 82.6 miles (132.9 km) of the highway, the only portion paved during the late 1960s and 1970s. Public Works Canada manages the highway from Mile 82.6 (km 133) to Historic Mile 630. The Yukon government owns the highway from Historic Mile 630 to Historic Mile 1016 (from near Watson Lake to Haines Junction), and manages the remainder to the U.S. border at Historic Mile 1221. The State of Alaska owns the highway within that state (Mile 1221 to Mile 1422).
The Alaska Highway was built for military purposes and its route was not ideal for postwar development of northern Canada. Rerouting in Canada has shortened the highway by approximately 35 miles (56 km) since 1947, mostly by eliminating winding sections and sometimes by bypassing residential areas. The historic milepost markings are therefore no longer accurate but are still important as local location references. Some old sections of the highway are still in use as local roads, while others are left to deteriorate and still others are plowed up. Four sections form local residential streets in Whitehorse and Fort Nelson, and others form country residential roadways outside of Whitehorse. 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.
Rerouting continues, expected to continue in the Yukon through 2009, with the Haines Junction-Beaver Creek section covered by the Canada-U.S. Shakwak Agreement. The new Donjek River bridge was opened 26 September 2007, replacing a 1952 bridge. Under Shakwak, U.S. federal highway money is spent for work done by Canadian contractors who win tenders issued by the Yukon government. The Shakwak Project completed the Haines Highway upgrades in the 1980s between Haines Junction and the Alaska Panhandle, then funding was stalled by Congress for several years.
The Canadian section of the highway is now approximately 1,187 miles (1,910 km), but the first milepost inside Alaska is 1222. The actual length of the highway inside Alaska is no longer clear because rerouting, as in Canada, has shortened the route, but unlike Canada, mileposts in Alaska are not recalibrated. The BC and Yukon governments and Public Works Canada have recalibrated kilometre posts. 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.
There are historical mileposts along the B.C. and Yukon sections of the highway, installed in 1992, that note specific locations, although the posts no longer represent accurate driving distance. There are 80 mileposts in B.C., 70 in Yukon and 16 in Alaska with a simple number marker of the original mile distance. There are 31 "historic signs" in B.C., 22 in Yukon and 5 in Alaska, identifying the significance of the location. 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 portion of the Alaska Highway in Alaska is designated Alaska Route 2. In Yukon, it is Highway 1 and in British Columbia, Highway 97. The portion of the Alaska Highway in Alaska was planned to become part of the United States Numbered Highway System, and to be signed as part of U.S. Route 97. The portion of the Alaska Highway in Alaska is also unsigned Interstate A-1 and unsigned Interstate A-2.