Esrum Å is the principal drainage of Lake Esrum, Denmarks second largest lake, located in Gribskov Municipality, some 50 km north of Copenhagen, Denmark. The 10-km-long stream extends from the northwestern part of the lake and flows past Esrum Watermill and Esrum Abbey on its way to The Kattegat at Dronningmølle. It is 10 km long.
