Rincón de la Vieja National Park, National park in Guanacaste Province, Costa Rica.

Rincón de la Vieja National Park is a protected area in Guanacaste containing two volcanoes, numerous rivers, and forest types ranging from mountain heights to lower elevations. The terrain displays a mix of tropical and cloud forest ecosystems adapted to different altitude zones.

Rincón de la Vieja National Park was created on 16 November 1973, covering about 1,200 hectares of the Cordillera Volcánica de Guanacaste between roughly 700 and 1,916 metres. In 1999 it was inscribed as part of the Area de Conservación Guanacaste UNESCO World Heritage site. The Santa María sector was formerly one of the main haciendas of the zone before its incorporation into the park.

The name Rincón de la Vieja, "the old woman's corner", refers to a legend of a woman who lived on the volcano. The Santa María sector was one of the main haciendas of the zone until it was incorporated into the park, and the Las Pailas sector takes its name from the fumaroles and hot pools of its volcanic ground.

The main entrance sector is open Tuesday through Sunday, and visitors should plan ahead since entry reservations are required beforehand. Good hiking shoes and plenty of water are essential, as trails can be uneven and sun exposure is intense.

The park contains visible volcanic phenomena like steam vents and boiling mud pools that reveal how geologically active the land remains. In certain areas, visitors can experience waterfalls and geothermal hot springs within the same landscape.