Wrangell-St. Elias National Park and Preserve includes the entire Wrangell range, the western portion of the Saint Elias Mountains and the eastern portion of the Chugach Mountains. Lesser ranges in the park or preserve include the Nutzotin Mountains, which are an extension of the Alaska Range, the Granite Range and the Robinson Mountains. Broad rivers run in glacial valleys between the ranges, including the Chitina River, Chisana River and the Nabesna River. All but the Chisana and Nabesna are tributaries to the Copper River, which flows along the western margin of the park and which has its headwaters within the park, at the Copper Glacier. The park includes dozens of glaciers and icefields. The Bagley Icefield covers portions of the St. Elias and Chugach ranges, and Malaspina Glacier covers most of the southeastern extension of the park, with Hubbard Glacier at the park's extreme eastern boundary, the largest tidewater glacier in North America. The eastern boundary of the park is Alaska's border with Canada, where it is adjoined by Kluane National Park and Reserve.