Hellevoetsluis grew after 1600 to become the most important war port in Holland. The ships of the Admiralty of Rotterdam were cleaned, repaired and equipped here.
Over the years, a modest village developed on either side of the Dok and Haven. As a result of the Second English War, the first defenses were constructed in 1665. Thirty years later, work began on a new fortification system, giving the naval port its distinctive shape that is still recognizable today.
In 1830 the Kanaal door Voorne was dug straight through the Nieuwenhoorn polder, after which Hellevoetsluis increasingly assumed the role of outport of Rotterdam. Thousands of ships passed through the lock every year, so that a lively trade developed in Hellevoetsluis and the many passers-by could find the necessary entertainment.