The navigational regime applicable to a strait, which is not governed by treaty, depends on its use for international navigation.

Past use of the Northwest Passage

Navigation in the Northwest Passage has taken place mainly for the purpose of exploration and adventure, before 1945, but also for security and economic reasons, since 1945.

Use of the Northwest Passage before 1945

Efforts to find a sea route to Cathay across the top of North America began with John Cabot in 1497 and lasted for nearly 400 years. Between Martin Frobisher's first expedition in 1576 and that of Sir John Franklin in 1845–7, some 40 expeditions, most of them British, sailed to the Arctic. The expeditions which contributed the most to the actual discovery of the Northwest Passage were those led by Lieutenant William E. Parry (1819–20,1821–3,1824–5), Sir John Ross (1829–33) and Sir John Franklin (1845–7). The routes followed by those expeditions are shown on Figure 21. During the 12-year period after the tragic loss of Franklin's expedition, over 75 search expeditons were sent to the Canadian Arctic. They resulted in the discovery and exploration of virtually all of the bodies of water which now constitute the main routes of the Northwest Passage (see Figure 13).

As already indicated in Chapter 8, Canada began sending expeditions to the Canadian Arctic shortly after the transfer of the Arctic Islands by Great Britian in 1880, in order to consolidate its title to the islands and exercise a certain degree of control over the waters of the Archipelago. Today, all of the routes of the Passage have been fully explored.