Fort-Mardyck (French pronunciation: [fɔʁ maʁdik]; Dutch: Fort-Mardijk; West Flemish: Fort-Mardyk) is a former commune in the Nord department in northern France.
The fort was again besieged and captured by an Anglo-French force under the Comte de Turrenne on 21 September 1657.
Turrene handed the fort over to the English Commonwealth in accordance with the terms of their involvement.
The following month the Spanish attempted to retake the fort one last time but the English garrison managed to repel the assault.
On 12 February 1867, a French imperial decree established Fort-Mardyck as an independent municipality.