Ølsted is a small town located south of Frederiksværk, between Lake Arre to the northeast and Roskilde Fjord to the west, in Halsnæs Municipality, some 50 km northwest of Copenhagen, Denmark. As of January 1. 2023, the town has a population of 1,938. It belongs to the Halsnæs municipality in Region Hovedstaden.

Frederiksværk is a town with a population of 12,815 in Halsnæs Municipality on Zealand in Region Hovedstaden in Denmark.