Lake Esrum (Danish: Esrum Sø) is the largest lake in Denmark by water volume and the second-largest lake by surface area, after lake Arresø. It is situated in the central part of North Zealand (the northeastern region of Zealand), straddling the boundaries of the municipalities Hillerød, Fredensborg, Helsingør and Gribskov, some 40 kilometres north of Copenhagen.The lake covers 17 km², Its length from north to south is 8.4 km and its maximum depth is 22 m.