On December 20th, 1982, this nature haven became a national park.

Located in the Guanacaste province, it contains the Tempisque Valley area and protects 16,804 hectars of mainly wetlands. It has been credited with more than 279 species of birds, among them the Jabiru which unfortunately, it is in serious danger of extinction. Also, other animals seen here are mammals like monkeys, squirrels, deer, and porcupine.

During the rainy season (April-November) it is usually flooded causing a natural hydrologic system creating an ideal area for the biggest concentration in Costa Rica and Central America for water birds, both migratory and residents.