With a boundary over 2,340 kilometers (1,450 miles) long, the Canada–Alaska frontier crosses through some of the wildest country and forests in North America. In some locations, the international boundary is obvious, like those clearly demarcated and maintained sections through the forested portions of the Yukon River Valley, but the borderline is completely invisible in other regions, like those along the summit of Mount St. Elias at 5,489 meters (18,008 feet) high. The initial border delineation occurred between Russia’s Alaskan Territory and the United Kingdom in 1825 and was reaffirmed in 1867 by the United States after its purchase of the Alaska Territory. An arbitral tribunal mediated a boundary dispute between the United Kingdom and the United States in 1903 after the discovery of gold in the region. The entirety of the boundary has been demarcated, and an active, bilateral demarcation commission maintains the markers and survey information in modern datums.

Canada and the United States also share the longest international land boundary in the world.