The Aa of Weerijs is a river which rises in Belgium, where it arises from the confluence of the Great Aa (in Wuustwezel) and the Small Aa (in  Brecht). In Breda (which means the broad Aa ) it is the river in the canals of this city. The name Broad Aa is a reference to its confluence with the Upper Mark. The conjoined rivers continue flowing as the  Mark. The width of the Aa of Weerijs varies from 5 meters to the border with Belgium up to 15 meters in Breda. The valley is about 3 kilometers wide.