Dülken is a town located in the North Rhine-Westphalia state of Germany. It has a population of about 20,000. It is part of the municipality of Viersen. It received its town charter in 1364 thus being the oldest part of the municipality of Viersen. It lies in the administrative region of Düsseldorf. The river Nette having its source underground in the middle of the town rises near the town.