Rincón de la Vieja National Park (Spanish: Parque Nacional Rincón de la Vieja), is a National Park in Guanacaste Province of the northwestern part of Costa Rica.
The park has a variety of wildlife, such as over 300 species of birds, such as the three-wattled bellbird (Procnias tricarunculata) and emerald toucanet (Aulacorhynchus prasinus), and also various quetzals, curassows, eagles, etc. Mammals seen in the park include cougars, monkeys, kinkajous, jaguars and many more. The volcanic vents and geysers are habitat for certain extremophile micro-organisms (C.Michael Hogan. 2010).