Westmaas is a village in the Dutch province of South Holland. It is located about 14 km south of the city of Rotterdam, next to Mijnsheerenland in the municipality of Binnenmaas.
Westmaas was a separate municipality between 1817 and 1984, when it became part of Binnenmaas.
Coordinates: 51°47′N 4°28′E / 51.783°N 4.467°E