Los Glaciares National Park is a federal protected area in Santa Cruz Province, Argentina. The park covers an area of 726,927 ha, making it the largest national park in the country. Established on 11 May 1937, it houses a representative sample of the Magellanic Subpolar Forest and western Patagonian Steppe biodiversity in good state of conservation. In 1981 it was declared a World Heritage Site by UNESCO.
The park's name refers to the giant ice cap in the Andes range that feeds 47 large glaciers, of which 13 flow towards the Atlantic Ocean. The ice cap is the largest outside of Antarctica and Greenland. In other parts of the world, glaciers start at a height of at least 2,500 m above mean sea level, but due to the size of the ice cap, these glaciers begin at only 1,500 m, sliding down to 200 m Los Glaciares borders Torres del Paine National Park to the south in Chilean territory.
Los Glaciares, of which 30% is covered by ice, can be divided in two parts, each corresponding with one of the two elongated big lakes partially contained by the park. Lake Argentino, 1,466 km² and the largest in Argentina, is in the south, while Lake Viedma, 1,100 km², is in the north. Both lakes feed the Santa Cruz River that flows down to Puerto Santa Cruz on the Atlantic. Between the two halves is a non-touristic zone without lakes called Zona Centro.
The northern half consists of part of Viedma Lake, the Viedma Glacier and a few minor glaciers, and a number of mountains very popular among fans of climbing and trekking, including Mount Fitz Roy and Cerro Torre.
The southern part has, as well as a number of smaller ones, the major glaciers which flow into Lake Argentino: Perito Moreno Glacier, Upsala Glacier, and Spegazzini Glacier. Typical excursion boats travel between icebergs to visit Bahia Onelli, and the otherwise inaccessible Spegazzini and Upsala. The Perito Moreno is reachable by land.