San Germán is a historic town and municipality located in the Sabana Grande Valley within the southwestern region of Puerto Rico. It is situated south of Mayagüez and Maricao, north of Lajas, east of Hormigueros and Cabo Rojo, and west of Sabana Grande. The municipality is organized into eighteen barrios plus the San Germán Pueblo.
As the second oldest city in Puerto Rico after San Juan, San Germán serves as a principal city for both the San Germán–Cabo Rojo Metropolitan Statistical Area and the Mayagüez–San Germán–Cabo Rojo Combined Statistical Area. Its historic downtown is preserved as the San Germán Historic District.