San Antonio is a barrio located in Quebradillas, a municipality in the northern coastal region of Puerto Rico. Within Quebradillas, San Antonio occupies approximately 15.76 square kilometers and forms part of the municipality's interior geography, positioned away from the immediate coastline that characterizes Quebradillas' northern edge. The barrio sits in an area that transitions between coastal lowlands and the gently rolling terrain typical of northern Puerto Rico's interior zones.

The landscape of San Antonio reflects its position in Quebradillas' hinterland, characterized by the subtropical climate and vegetation patterns common to this part of the island. The terrain here supports a mix of residential development, agricultural land, and open space, typical of barrios in this region that have not experienced the dense urbanization seen in immediate coastal or metropolitan areas. Property ownership in San Antonio encompasses various parcel sizes, from smaller residential plots to larger agricultural tracts, reflecting the historically mixed-use character of interior barrios in Quebradillas.

As with all barrios in the municipality, San Antonio's property records are managed through Puerto Rico's cadastral system maintained by CRIM, which documents the ownership, boundaries, and legal status of all parcels throughout the territory. Researchers and property owners investigating land and real estate in San Antonio can access detailed cadastral information and ownership records through Propieda's property research platform.

Quebradillas: Quebradillas, on the northwest coast, offers dramatic coastal cliffs, the Guajataca Tunnel, and small-town atmosphere. The municipality provides affordable coastal living with natural attractions. Property options include clifftop views, beach access, and agricultural land.