Hollands Diep is a river in the Netherlands, and an estuary of the Rhine and Meuse rivers. Through the Scheldt-Rhine Canal it connects to the Scheldt river and Antwerp.
The Bergse Maas river and the Nieuwe Merwede river (New Merwede) join near Lage Zwaluwe to form the Hollands Diep.
The Dordtsche Kil connects to it near Moerdijk.
Near Numansdorp it splits into the Haringvliet and the Volkerak estuaries.
