Laguna de Aculeo, Lagoon in Paine, Chile

Laguna de Aculeo is a shallow freshwater lagoon in the commune of Paine, Maipo Province, about 50 km southwest of Santiago. According to a 2010 survey by Chile's General Water Directorate, its water surface covered 11.5 km², with a mean depth of 3.4 m and a maximum of about 5 m. It has muddy shores and gentle slopes along its margins, and two small islands in its western section.

The lake received its name from the Mapuche people who inhabited the region before colonial times. During the 20th century, it became a leisure destination for people from Santiago seeking outdoor recreation.

The name derives from Mapudungun Acum-Leu, "where the river ends". A local legend holds that an entierro, a treasure, has lain hidden in the lake bed since 1814. A wampo, a canoe carved from a single boldo trunk and holding two or three people, is kept by a local family.

The lagoon lies about 50 km southwest of Santiago in the commune of Paine, Maipo Province. Its natural outlet is the Estero Aculeo, dry in summer and carrying little water in winter, while the Estero Pintué feeds it. Shores are muddy with gentle slopes, so access on foot changes with water level; the lagoon refilled after the 2023 and 2024 rains.

NASA's Landsat images recorded the lagoon's complete drying on 10 April 2018; by 2019 the former bed was mostly dry mud and vegetation. After the winter storms of 2023, satellite data showed about 5 km² of water roughly 1 m deep on 7 September 2023, around half the pre-2010 area and a quarter of its former volume. A 2025 study put the lagoon at about 90% of its historical level after two wet years and the release of Pintué River diversions.