Size: 217 hectares
Distance from San José: 84 kilometers
Camping: Permitted
Dry season: December through April

Guayabo is the largest and most important archeological site discovered to date in Costa Rica. It appears that human occupation of the area goes back as far as 500 B.C., although it was from 800-1400 A.D. when the chiefdom truly flourished and when the stone structures that can be seen today were built. Guayabo held an important political and religious position and its influence was spread over a large area. It is thought that the center of the chiefdom was surrounded by a number of small villages with a rural population of between 1,500 to 2,000 people who served as a source of labor and revenue. Judging by the handsome pottery and finely wrought gold and stone artifacts, it would seem that the inhabitants enjoyed an elevated cultural status. The rise of Guayabo was also due to its strategic location as a transition point between the Atlantic lowlands and the high central plateau.

The archeological value of Guayabo has been known since the end of last century when several expeditions were carried out to collect artifacts for museums and private collections, and to complete the archeological collection that Costa Rica exhibited at the Historical-American Exhibition in Madrid in 1892, which was held to commemorate the fourth centennial of the discovery of America.
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The main architectural structures that remain, of which over 50 have been excavated to date, consist of cobble-paved causeways (use as stone house foundations), open and walled-in aqueducts many of which are still in use, and water tanks, rectangular structures used for collecting water from aqueducts. The architectural structures vary greatly in shape and size.

The most prevalent shapes are the circle, rectangle and ellipse, although some of the mounds have an irregular shape. With regard to size, the area where the mounds have been located varies from 4 to 700 square meters, and the largest structure is a square that measures 888 square meters. The building materials used were round stones of about 40-50 cm. In diameter that were placed in rows, sometimes very close together and with the flattest side face-up, and slabs of different lengths, some up to 5 meter long.
The stone objects that most attract the visitor's notice are the monoliths and petroglyphs.

One of the most interesting monoliths discovered is a wedge-shaped boulder, 1.4 meters long by 0.56 meters wide, which displays a quadruped on one side, a lizard, and on the other an animal with a rounded head and a long, spindle-shaped body, a jaguar. Petroglyphs can be found everywhere. Some represent animals such as birds and felines while others seem to have no meaning at all. Golden bells have also been found in the area, together with a gold and copper frog, an obsidian arrowhead, a fragment of a carved wooden staff, monolithic tables, a sacrificial stone, a platter, pottery, ashes and roasted corn kernels. One of the most extraordinary artifacts that has been excavated is a tablet made of a single block of stone that measures 186 cm. Long, 60 wide, and 5 cm. Thick. The edges of the entire tablet are carved with animal figures. Today this work of art is housed in the National Museum.

The most serious management problem facing the park is the conservation of the stone structures which on being excavated have a tendency to shift, erode or sink into the ground. This has led to carrying out several kinds of stabilizing repairs at the same time that the excavations have continued with the aim of providing visitors with a tour of the entire archeological area in the not too distant future.