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

San Germán barrio-pueblo is a barrio and the administrative center (seat) of San Germán, a municipality of Puerto Rico. Its population in 2010 was 2,660.