Proposals for a road linking the contiguous United States to Alaska circulated from the 1920s, championed by Thomas MacDonald of the Bureau of Public Roads and dramatised by Slim Williams's 1933 dog-sled journey along the proposed route. Canada under Mackenzie King repeatedly refused, fearing a US-funded highway across its territory would drag it into a Pacific war. Pearl Harbor changed everything: the Army approved construction in February 1942, Canada consented on condition the US paid every penny and handed over the Canadian section after the war, and the Army Corps of Engineers chose Route C to link the airfields of the Northwest Staging Route feeding Lend-Lease aircraft to the Soviet Union.

Over 10,000 men, roughly a third of them segregated African American troops of the 93rd, 95th and 97th regiments, punched a pioneer road from Dawso ...