Located on the Central Volcanic Cordillera, 31km to the west of the city of Cartago. It was created with the Nº 1917 article from the Organic Law created by the Institute of Tourism on the 30th of July 1955. From 1970 the services of the national parks manage this national park. It has an extension of over 2.309 hectares. It is an area of great hydrological importance. It is here where several rivers flow into the Río Chirripo, Río Reventazon, Río Sarapiquí and Río Grande de Tarcoles.
The origin of its name is due to the indigenous population that lived on the outskirts of the volcano called Iztarú, a word that for them meant tremor and lightning, nevertheless, through the years, oral communication meant that the name gradually changed to Irazu. The main point of interest in the national park is Irazu with an altitude of 3.432 meters; it is an active volcano and is the tallest in Costa Rica. Its eruptions and those of other volcanoes have made the land of the central plateau more fertile. Eruptions have been recorded since 1723, when the Governor of that Province of Costa Rica, Diego de la Haya Fernandez, gave a description about what had happened. One of the main craters is actually named after him. The last significant eruption of Irazu was memorable. It happened on the 19th of March 1963; the eruption coincided with the arrival of the President of the United States John F. Kennedy. In San José, Cartago and almost all of the Central Plateau was covered in centimeters of ash; in some areas there was more than half a meter. The agricultural land to the northeast of the volcano was temporarily uninhabited because of rocks and boulders that had been displaced from the crater. Since then the activity has been reduced to soft and humid smoking emissions. The summit is barren with ash and craters. The main crater measures 1.050 meters in diameter and has a depth of 300 meters; Diego de la Haya has a diameter of 690 and a depth of 100 meters and a small lake. But there are two smaller openings; one of them also has a lake. There is also a pyroclastic cone that was formed by the volcanic activity. From the car park to the viewpoint, footpaths have white and blue signposts, there are also signs pointing out restricted areas. From the top of the volcano it is possible to see the Pacific and the Caribbean. The summit is cold, windy and cloudy with temperatures of 3°C to 17°C with a yearly rainfall of 2.160 mm.
Tel (506) 2551-9398, regional office. An asphalt road takes you close to the summit where you can park and there is also an information office. There is also a souvenir store. During the dry season and the weekends they sell snacks and simple meals; although there is no accommodation or camping area, open from 8.00am to 03:30 pm, entry is 6 US$ per person.