Walker Glacier fills the valley below a wildflower-studded hillside in Glacier Bay National Park just above the Alsek River in the Saint Elias Mountains of southeast Alaska. Glacier Bay Park extends south from here and encompasses a vast expanse of mountains and glaciers all the way to Dundas Bay, 100 miles south of this location. Together with Kluane and Wrangell Saint Elias Parks to the north, Glacier Bay forms one of the largest parcels of protected land on the planet.