During the colonial period in Costa Rica poverty ruled. The indigenous settlements in the Central Valley were decimated by the conquistadors and their illnesses; those few that survived fled to the mountains to avoid Spanish slavery.

There were no grand palaces nor magnificent cathedrals built locally, the Spanish colonos (Spanish born inhabitants, given lands by the Crown) had no cheap labour to rely on as in other Spanish provinces. They had to tend the lands practically by themselves. Small adobe houses or wood houses with tejas (roof tiles made of baked mud) were the standard then.

There are only two colonial monuments left in Costa Rica, both very humble: The Orosi Church and the Ujarrás Ruins. From the Ujarrás church built in the 1800's, only restored ruins remain. Thus, the only colonial church that still stands upright is the Orosi one.

A small settlement was first founded in the Valley of Orosi during the XVII century, but in 1699 it was moved to another area since the inhabitants were few and the area considered unhealthy.

The missionaries at the time, led by Franciscans, were set on spreading the gospel to the indigenous people from the mountains of Talamanca (the mountain range that lies on the border between Costa Rica and Panama) but they had run into problems. Around the 1740's, when the Spanish missions were withdrawing, Orosi was repopulated.

According to the legend the Franciscans came to Orosi with some loyal Talamancan indians, carrying on their shoulders a statue of Saint Joseph, chanting psalms and ringing a small silver bell. They had had to flee the ruins of the Saint Joseph church in the town of Cabécar which had been burnt by «unfaithful Talamancans.» When they went through the hot springs and made their way to the small valley ahead, the silver bell went quiet. The Franciscans decided then that a church would be built in that same spot.

Shortly after built the church was destroyed by a river nearby. It was rebuilt and again it was flooded by the river. After many days of prayers and penance the Franciscans decided that the church should be built looking towards the east, contrary to all the other catholic churches built traditionally looking towards the west. The Franciscans claimed that Saint Joseph, standing on the main altar, needed to be looking to the east, towards his beloved Cabécar. Since then, the legend says, the river withdrew and let the church be.

It is difficult to determine the exact date Orosi's church was built. There is a report filed by the friar Francisco Reygada, in charge of the missionary school in New Guatemala. This report dates from 1797 and states: «...It's been 54 years since the Orosi convent was founded...» If friar Reygada's report is accurate, then 1743 seems to be the correct date.

Orosi's church was declared a National Monument in 1985 and many works of art can be admired inside, including religious paintings, sacred images and the altar. The adjacent museum contains pieces and artefacts used by the Franciscans during the missionary period, and provide a good idea of what the lifestyle of that era was like.

According to specialists hot springs waters are effective for relieving muscular pain, helping physical rehabilitation, and reducing stress. There are presently two pools in Orosi with good facilities for tourists to come and bathe in the waters.

A look out point known as the Mirador de Orosi provides and excellent view of the valley. The Mirador is part of a park, it offers clean rest rooms, several picnic tables including some that are covered, parking, and paved walking paths.