The Daade (also called the Daadenbach) is the largest tributary of the River Heller, in the district of Altenkirchen in the northeast of the German state of Rhineland-Palatinate. It flows through the northeastern part of the Westerwald. It is long and has a catchment area of .
The Daade Valley Railway runs along the Daade from Daaden via Alsdorf to Betzdorf, on the main line from Cologne to Siegen.
The villages on the Daade are:
The tributaries of the Daade (in downstream order) are the:
All left tributaries have their sources on the Neunkhausen-Weitefeld Plateau, but cut deep valleys in the Heller Upland.