The Citadel of Lille (French: Citadelle de Lille; Dutch: Citadel van Rijsel) is a pentagon-shaped citadel of the city wall of Lille, in France. It was built around 1668. It hosts the Corps de réaction rapide France.
Dubbed "Queen of the citadels" (Reine des citadelles) by Vauban, it is one of the most notable citadels designed by Vauban. The citadel was part of a double line of fortified towns of Gravelines, Dunkirk and Maubeuge-Rocroi. It was famous pré carré ("square field"), conceived by Vauban comprising 28 fortified cities.
Starting from Lille, Vauban supervised the construction of the many citadels and channels of the North, which controlled the border between France and Belgium.