The Brielse Maas is a dammed river between the North Sea and the Oude Maas in the southern part of the Dutch province of South Holland. The town of Brielle, which gave it its name, is located on the south bank. The Brielse Maas was dammed before the flood of 1953. Originally the Brielse Maas was part of the Nieuwe Maas: at the Vondelingenplaat the Oude Maas and the Nieuwe Maas came together and split into the Brielse Maas and the Scheur. The area between Scheur and Brielse Maas was the island of Rozenburg.