Argentino Lake, Glacial lake in Santa Cruz Province, Argentina

Argentino Lake is a glacial lake in Santa Cruz Province with a main body and two long western arms inside Los Glaciares National Park. Its surface lies at 178 m above sea level, and the Upsala and Perito Moreno glaciers calve into its arms. The water appears pale blue-green, with floating ice blocks and dark, snow-patched mountains behind.

In November 1873, sub-lieutenant Valentín Feilberg of the Argentine schooner Chubut explored the lake's shores by boat. First charted as "Santa Cruz", it was renamed Lago Argentino by Perito Pascasio Moreno, who compared its deep blue water to the Argentine flag. At its eastern end stood Carr Aiken, an Aonikenk stopping place near the mouth of the Santa Cruz River.

The Aonikenk called the lake Kelta, though no historical record confirms it. Explorer Pascasio Moreno renamed it Lago Argentino, comparing its intense blue water to the Argentine flag. At the eastern end, near the Santa Cruz River mouth, stood an Aonikenk aike called Carr Aiken.

The lake's two western arms lie inside Los Glaciares National Park, where the Upsala and Perito Moreno glaciers calve into the water. El Calafate, on the southern shore, is the usual base; the lake is reached from Punta Bandera. The north-northwestern arm ends in front of the retreating Upsala Glacier.

In 2001 a survey found the lake's deepest point, 719 m, at the end of its narrow north-northwestern arm in front of the retreating Upsala Glacier. The glaciers cut trenches into the bedrock where they enter the water, and the lake surface lies 541 m below mean sea level.