Fort Richelieu is a historic fort in the Canadian La Vallée-du-Richelieu Regional County Municipality, Quebec. Fort Richelieu was part of a series of five forts built along the Richelieu River and is at the mouth of the Richelieu River. Fort Chambly formerly known as Fort St. Louis at Chambly, Fort Sainte-Thérèse, and Fort Saint-Jean at Saint-Jean-sur-Richelieu, are on the way. The forts were built in order to protect travellers on the river from the Iroquois. The region is informally known as la Vallée-des-Forts. It was built by Charles Huault de Montmagny, first Governor and Lieutenant-Governor of New France, and named in honour of Cardinal Richelieu, chief minister to Louis XIII. The fort was burned down by the Iroquois in 1647. In 1665, the Carignan-Salières Regiment, under the direction of Pierre de Saurel, rebuilt the fort on the same site.