The Pacific Cordillera (Canada) is a top-level physiographic region of Canada. This cordillera is part of the North American Cordillera. The mountain ranges in this region were covered during the Pleistocene by the Cordilleran Ice Sheet. The extent of the Cordilleran ice sheet gives perspective on the geographic extent of this region, extending from coastal mountains in Alaska, south through most of the Yukon and British Columbia, bordered by the Rocky Mountains to the East, to stretch its margin beyond the Canada-US border with five extensive lobes reaching into the mountain valleys of Montana and Washington.