 The Dadau has its source in the Diepholz Moor Depression in the Südlohn Moor near the town of Lohne.Then it flows northwards between the Südlohn and Brägel Moors to the west and the Aschen Moor to the east and then turns to head east at the boundary between Lohne and Vechta on its left bank.Beyond the B 69 federal road, the Dadau flows in an easterly, and sometimes south-easterly, direction.