Lago del Desierto Provintial Reserve, Nature reserve in Santa Cruz Province, Argentina

Lago del Desierto Provincial Reserve covers 59,982 hectares in the Lago Argentino department of western Santa Cruz, Argentina, from the lake and international boundary milestone No. 62 to Los Glaciares National Park. Its terrain combines steep mountains, glaciers and moraines, rivers, lagoons and wooded valleys; the reserve holds the Huemul, Milodón and Marconi glaciers and the De las Vueltas/Gatica river, and huemul deer live within it.

The reserve was created by Law No. 2820, passed by the Santa Cruz Legislature on 10 November 2005. It covers 59,982 hectares around Lago del Desierto and the international boundary sector from milestone No. 62 to Los Glaciares National Park. The southwest holds Marconi Pass, a crossing to Chile by the southern Patagonian ice field, while the Dos Lagunas border crossing lies to the north, reached by a hiking trail 16 km from the Chilean town of Candelario Mancilla.

The reserve's name comes from Lago del Desierto, the lake at its centre; the lake and the international boundary sector from milestone No. 62 to Los Glaciares National Park are what the protected area covers. The reserve was created by law No. 2820, passed by the Santa Cruz Legislature on 10 November 2005. Huemules live in the reserve, and the Marconi Pass in the southwest is a crossing between Chile and Argentina in the southern Patagonian ice field.

Access to the area is typically through the village of El Chaltén, where several hiking trails begin. The best time to visit is during the southern summer between December and March, when trails are most accessible and weather is more stable.

The lake is fed by four major glaciers - Huemul, Milodon, Cagliero, and Marconi - which together create the clear waters visitors see today. These glaciers can be reached on longer hikes from different starting points and offer direct views of active ice formation.