Rincón de la Vieja is an active andesitic complex volcano in north-western Costa Rica, about 23 km (14 mi) from Liberia, in the province of Guanacaste.

Rincón de la Vieja is one of six active Costa Rican volcanoes: the others are Poás, Irazú, Miravalles, Arenal, and Turrialba.

[4] In 2013, the extension of the Las Pailas Geothermal Power Plant to 55 megawatt, financed in part by a credit from the European Investment Bank, was started.

Trails extend from the Santa Maria ranger station and wind through the park, passing hot springs and waterfalls along the way.

Mammals within the park include sloths, tapirs, kinkajous, pumas, jaguar, and both howler and spider monkeys.