O'Higgins/San Martín Lake

O’Higgins / San Martín Lake is a large glacial lake in southern Patagonia that lies on the border between Chile and Argentina. It is fed by glaciers and sits in a remote mountainous region of the southern Andes.

The lake is valued for its scale and glacial scenery, with long, fjord-like arms and ice-fed waters; boat trips from the Chilean side access nearby glaciers and icefields. The shorelines are largely undeveloped, so the experience is predominantly natural rather than urban.

The basin formed and was shaped by Pleistocene glaciation and continued glacial activity, which feed the lake and surrounding rivers. Over the 20th and 21st centuries access has remained relatively limited, preserving much of the lake’s natural character.

Geographically the lake sits deep in southern Patagonia, straddling the Chile-Argentina border in the southern Andes. Nearest major centers are hundreds of kilometres away; the area is dominated by mountains, glaciers and temperate-patagonian vegetation.

• Two-country name: Known by two names - O’Higgins on the Chilean side and San Martín on the Argentine side - reflecting its position on the international border.

• Remember the lake has two names-O'Higgins in Chile and San Martín in Argentina-and the most practical public access point is from Villa O'Higgins on the Chilean side via the Carretera Austral; plan logistics around that end.
• Visit in the Southern Hemisphere summer (December-February) when boat services and weather are most reliable and the glacier-fed icebergs and shoreline viewpoints are at their most visible.
• Book any boat excursions in advance and aim for the early departures of the day to increase chances of calmer water and clearer visibility of glacial fronts and icebergs that many day visitors miss.