Arresø -the biggest lake in Denmark.
A charming character of the nature in Noth Sealand is the changing weather. But regarding the weather or maybe because of the weather – is a trip to Arresø a great nature experience.
Arresø is the biggest lake in Denmark and is owned by the Ministry of the Environment. It borders to three municipalities (Halsnæs, Gribskov and Hillerød). The lake has an outflow to Roskilde Fiord through the canal in Frederiksværk.
There are a number of rivers and streams running into the Arresø of which the Pøleå is the most significant. Especially along the lake's west side there are a number of hills and ridges. Among these is Maglehøj in the Frederiksværk and Arrenakke Hills, which offers a magnificent view over the lake.
The job to establish the Arresø canal was ended in 1719. From the 1750 and the years ahead the water power was used for the powder mill in Frederiksværk, which until 1965 still was in action but today is a museum.

Esrum Esrum Lake is 20 m deep in some places and should be treated with respect. You can bathe in a few spots close to the bank. Esrum Lake is Denmark’s second biggest lake and is shaped like a bathtub, with sheer inclines not far from the lake edge and a large, relatively flat bottom. The lake has a rich bird life. There are several barbecue sites along the lake.

Gurre Lake is located in the forest, close to Horserød. The major part of the forest that extends to the lake edge is unprotected, so the lake area is exceptionally quiet and peaceful. The lake itself is about 20 hectares in size and 4 m deep.