The ice mass feeds dozens of glaciers in the area, among which are the Upsala (765 km2), Viedma (978 km2) and Perito Moreno (258 km2) in the Los Glaciares National Park in Argentina, and the Pío XI Glacier or Bruggen Glacier (1,265 km2, the largest in area and longest in the southern hemisphere outside of Antarctica), O'Higgins (820 km2), Grey (270 km2) and Tyndall (331 km2) in Chile. The glaciers going to the west flow into the fjords of the Patagonian channels of the Pacific Ocean; those going to the East flow into the Patagonian lakes Viedma and Argentino, and eventually, through the rivers de la Leona and Santa Cruz, to the Atlantic Ocean.