The San Pablo de Cabagan Church in San Pablo, Isabela is considered the oldest church in the province, built in 1624 during the Spanish colonial period as part of the early Catholic missions in the Cagayan Valley. The name “de Cabagan” reflects its historical origin, as the town of San Pablo was once under the larger and older jurisdiction of Cabagan during the early Spanish administration.

The church was built using brick, adobe, coral stones, and river materials, following a Baroque architectural style. Its façade features an arched entrance with simple decorative elements, and it originally had a six-level bell tower that was once among the tallest in the region.

The structure sustained major damage during World War II and was further affected by the 1949 earthquake, followed by a fire that destroyed the roof. For many years, it stood in a partially ruined state, with only sections of the walls, façade, and tower remaining.

Restoration efforts have since been completed, transforming the structure from a ruin into a functional heritage church. The nave is now fully covered with roofing, and the choir loft has been reconstructed, restoring key architectural components while preserving the original materials and layout.

Recognized as a National Cultural Treasure, the church now stands not as a ruin but as a restored historical structure that continues to reflect early church architecture in Isabela and northern Luzon.