The Alcan Highway, also known as the Alaska-Canadian Highway, is a 1,523-mile (2,450 km) road that connects Dawson Creek, British Columbia, Canada to Delta Junction, Alaska, United States. It was built during World War II as a strategic military route to connect Alaska to the lower 48 states.

The Japanese attack on Pearl Harbor on December 7, 1941, prompted the United States government to take action to protect Alaska from potential invasion. The U.S. Army Corps of Engineers began construction of the highway on March 8, 1942, as a way to move troops and supplies to Alaska quickly and efficiently. The highway was built by soldiers and civilian contractors, many of whom were tasked with working in the challenging conditions of the far north. The road was completed in just eight months, on November 20, 1942. The highway played a key role in the defense of Alaska during the war, and it remains an important transportation link for the state to this day.

The construction of the Alcan Highway was a joint effort between the United States and Canada. In February 1942, the U.S. and Canadian Governments agreed to jointly construct the highway, with the U.S. Army Corps of Engineers taking the lead on the project. The U.S. government provided the majority of the funding, while the Canadian government provided land, labor, and materials.

The two countries set up a Joint Defense Plan, which was signed on February 11, 1942, that outlined the details of the project, including the construction and maintenance of the highway, the sharing of costs, and the coordination of military and civilian efforts. The plan was approved by President Franklin D. Roosevelt and Prime Minister William Lyon Mackenzie King.

The Canadian government also provided a large number of workers for the construction of the highway, mainly from the Canadian Army's Pioneer Corps. The Canadian army also provided some of the equipment and supplies for the construction of the highway.

The cooperation between the US and Canada on the construction of the Alcan Highway demonstrated the strong relationship between the two countries, and it served as a symbol of the strong alliance between the two nations during World War II and beyond.

The construction of the Alcan Highway was driven primarily by military considerations. Following the Japanese attack on Pearl Harbor on December 7, 1941, the United States government became concerned about the potential for Japanese invasion of Alaska. The Alcan Highway was built as a strategic military route to connect Alaska to the lower 48 states, allowing for the quick and efficient movement of troops and supplies to the territory in the event of an invasion.

The highway also served as a means to protect the airfields and other military installations that were being built in Alaska during the war. The airfields were crucial for the defense of Alaska, as they provided a means for the United States to launch air raids on Japanese-occupied islands in the Aleutians.

The construction of the highway was completed in just eight months, on November 20, 1942, and it played a key role in the defense of Alaska during the war. The highway allowed the U.S. to quickly and efficiently move troops and supplies to Alaska, as well as allowing for the construction of airfields and other military installations that were needed to defend the territory.

It is worth noting that Japan never attempted to invade Alaska, but the construction of the Alcan Highway was an important aspect of the overall strategy for the defense of North America during World War II. The highway was also important in the protection of the supply route to the Soviet Union via Alaska-Siberia (ALSIB) which was a critical component of the Lend-Lease program during WWII.