fairly continuous ridge of north-south–trending mountain summits in western North America which divides the continent's principal drainage into that flowing eastward (either to Hudson Bay in Canada or, chiefly, to the Mississippi and Rio Grande rivers in the United States) and that flowing westward (into the Pacific Ocean). Most of the divide runs along the crest of the Rocky Mountains, through British Columbia and along the British Columbia–Alberta border in Canada, and through the states of Montana, Wyoming, Colorado, and New Mexico in the United States. It continues southward into Mexico and Central America, roughly paralleling the Sierra Madre Occidental and the Sierra Madre del Sur, with their associated ranges in Central America. In general usage the name continental divide is applied to the main water parting in any continent.