The scenic town of Monterey was founded by Father Junipero Serra and Don Gaspar de Portola on June 3, 1770, on the shores of Monterey Bay.

A year later, Fr. Serra moved his Mission to Carmel. The church remained as a Royal Chapel for the soldiers guarding the new Spanish Presidio of Monterey. The present sandstone church was built between 1791 and 1794, making it the oldest stone building in California. It is also California’s first cathedral, a status it first acquired in 1849 when Bishop Joseph Alemany chose it as the seat for the diocese of Monterey.

The original floor plan of the church was rectangular. Transepts were added in 1858 giving it the cross-shaped floor plan it has today. The replica of the Lourdes grotto to the left of the church was constructed in 1921.

By 2006, the church was 215 years old and showing its age; moisture was seeping into the walls, tree roots were destroying the foundation and previous alterations to the building had weakened it. The parish began a comprehensive restoration of the church which took three years and was completed in 2009. In the process, an archaeological dig turned up many artifacts that contributed important information to the early history of the Presidio of Monterey. This history is now showcased in the heritage center located next door to the church.

Today, the San Carlos Cathedral is embarking on its next 200 years as a stately witness to the history of Monterey.