60 kms from Alajuela along the route Varablanca-San Miguel you will reach a village called Río Cuarto. One kilometre from there is the lagoon.
This lovely lagoon, which covers 29 hectares and which is 15 meters deep, fills an ancient volcanic crater associated with a faultline that begins at Poás Volcano and connects Hule Lagoon and Congo Volcano (2,014 meters above sea level). It drains into the Caribbean by means of a small arm that feeds the River Cuarto. It is surrounded by steep, sheer cliffs but it can be reached from the eastern sector. A very hot and humid clump of woods grows around the lagoon, where a large number of cattle egrets return to roost every evening at sundown.