During the Age of Discovery, the Spanish Empire undertook several expeditions to the Pacific Northwest of North America. Spanish claims to the region date to the papal bull of 1493, and the Treaty of Tordesillas signed in 1494. In 1513, this claim was reinforced by Spanish explorer Vasco Núñez de Balboa, the first European to sight the Pacific Ocean, when he claimed all lands adjoining this ocean for the Spanish Crown. Spain only started to colonize the claimed territory north of present-day Mexico in the 18th century, when it settled the northern coast of Las Californias.

Alaska is a non-contiguous U.S. state on the northwest extremity of North America. It borders the Canadian province of British Columbia and the Yukon territory to the east; it shares a western maritime border in the Bering Strait with Russia's Chukotka Autonomous Okrug. The Chukchi and Beaufort Seas of the Arctic Ocean lie to the north and the Pacific Ocean lies to the south. Technically a semi-exclave of the U.S., it is the largest exclave in the world.