The water castle Gemen is in the Münsterland, in the former swamp area of the Bocholt Aa an smal creek. Although the name suggests otherwise, it is today at a palace. His former Castle Square is today Borkener - Gemen district.
The castle was built from the gradual rebuilding of more than 900 years old water castle which was built by the nobles of Gemen, one of the most influential Westphalian nobility of his time. It stands on two islands that are surrounded by an extensive systems of chanels. The palace was the center of the rule Gemen.