Fort Saint - Jean ( Quebec ) Fort Saint - Jean is a fort in the Canadian province of Quebec located on the Richelieu River . The fort was first built in 1666 by soldiers of the Carignan - Salières Regiment and was part of a series of forts built along the Richelieu River . Over the years , it was destroyed and rebuilt several times , but it is , after Quebec City , the military site that has been occupied non - stop for the longest time in Canada . The fort is designated as a National Historic Site of Canada , and it currently houses the Royal Military College of Saint - Jean . The fort has been continually occupied since 1748 , and is the core from which the city of Saint - Jean - sur - Richelieu , Quebec grew around . Fort Saint - Jean played a crucial role during the 1775 American invasion of the Province of Quebec . History . The First French Fort . In 1663 , the French King Louis XIV decided to take direct command of his New France colony , which had been previously colonized and managed by wealthy merchant associations . As the Iroquois were very often leading punitive expeditions on the New France territories and were continuously trying to steal away the French allies ' hunting territories , Louis XIV decided to send the whole Carignan - Salières Regiment to build a series of forts along the Richelieu River and Lake Champlain , which explains why the area was later named the Vallée des Forts ( literally : the Forts Valley ) , and to lead a punitive expedition against the Iroquois . The first Fort Saint - Jean was built along the Richelieu River by the Carignan - Salières Regiment in 1666 for that purpose . This first fort is believed to have been a small square - shaped fort with four bastions made of wooden palisades . It was located right after the Chambly rapids , a highly strategic position that allowed the French to monopolize a very good portage location . The French offensive into Iroquois territory was a great success and thus , a peace treaty was signed between the two parties in 1667 . In 1672 , after several peaceful years , the Governor of the colony decided to abandon several forts that had become useless along the Richelieu River , including Fort Saint - Jean . Because of its strategic location , Fort Saint - Jean was later to be revived , unlike others French forts such as Sainte - Thérèse and Sainte - Anne . The Second French Fort . The second French fort Saint - Jean was built in 1748 because of tensions between France and England arising from the War of the Austrian Succession . It was a fort of two hundred feet by two hundred feet that had four bastions , two of which were made in stone . This fort was an important relay between Montreal and Fort St . Frédéric , which was located in the south of Lake Champlain , because a road linked fort Saint - Jean to La Prairie and allowed the communications between Montreal and St . Frédéric to be considerably shorter . The second fort Saint - Jean was given the sympathetic nickname of “ Fort aux Maringouins ” ( Mosquitoes Fort ) because of the swampy climate of the area . This fort was destroyed by French soldiers in 1760 during the French and Indian War . As there were not enough men left to defend the fort against a three to five thousand - man British army coming up from the Richelieu River to take Montreal , the French decided to abandon the fort and before they left for Montreal , they put fire to it as to not leave it to their enemy . The stone bastions of the fort that survived the fire were afterward used as a relay by the British troops . The 1775 British fort and the American invasion . Because of the dangers posed by the thirteen rebellious colonies to the South , the British in 1775 erected a third fort on the site of the previous fort . A year before the Declaration of Independence transformed those rebellious colonies into the United States of America , two small armies of rebels invaded the Province of Quebec in an attempt to defeat the British on Canadian soil and to raise Canadian opposition to royal British rule . Fort Saint - Jean played a vital role in the defence of the Province of Quebec against the Americans ; indeed , it was the principal defense of Montreal against General Richard Montgomery ’ s army , which had planned to use the Richelieu River to reach Montreal , then march to Quebec City . The garrison of Fort Saint - Jean fought valiantly against the American troops during a forty - five - day siege before surrendering to the invaders . The siege of Fort Saint - Jean considerably weakened and slowed the American offensive : Montgomery ' s expedition arrived at Quebec City early in December instead of mid - October , and only three hundred of his men , out of about two thousand , actually reached to Quebec City . Because of bad weather and the weakened state of the few remaining troops , the Americans failed to take Quebec City in their assault on December 31 , 1775 . After British reinforcements arrived from England the next Spring , the Americans abandoned and burnt the forts , including Fort Saint - Jean , that they had taken north of Lake Champlain . But , fearing a new American invasion , the British reconstructed a strengthened Fort in 1776 , adding a series of new ramparts . They also built in Saint - Jean an important shipyard to assemble the shallow - draft boats needed to follow the Americans on Lake Champlain . These boats later soon would take part in the Battle of Valcour Island . The 19th - century fortifications . Fort Saint - Jean lost much of its importance after the end of the American War of Independence in 1783 and was only used as a relay during the second American Invasion in 1812 - 1814 . However , the Patriot Revolt episodes of 1837 - 1838 convinced the British of the need to fortify again fort Saint - Jean and new buildings were added to the fort . Some of those buildings , built in 1839 by the Royal Engineers , are still standing and being used nowadays on the site . At the end of the 19th and beginning of the 20th century , the fort was mostly used as a training school for several groups and regiments , the Royal Canadian Dragoons among them . During the First World War , the Royal 22 Régiment , who was back then only a battalion , was founded and trained at Fort Saint - Jean before being sent to Europe . After the war , the 22nd battalion became the first officially French - speaking Canadian regiment under the name of the Royal 22 Régiment ( known in English as the Vandoos ) . Known between the wars as Cavalry Barracks , fort Saint - Jean also served as a garrison for a Squadron and a company of The Royal Canadian Regiment . The CMR years . In 1952 , the Royal Military College Saint - Jean was created to allow a greater number of French - speaking Canadians to become officers in the Canadian Army , Royal Canadian Navy and Royal Canadian Air Force , thus becoming the first bilingual military college in Canada . Initially , only first - and second - year courses were offered and cadets had to complete the remainder of their education at the Royal Military College of Canada in Kingston , Ontario . Over time , the college began offering third - and fourth - year courses and in 1985 , it became accredited to grant its own diploma when it received its own Academic Charter . In 1995 , the Collège militaire royal de Saint - Jean ( CMR ) was closed due to budget cuts and classes were transferred to RMC Kingston . In order to maintain the CMR site and its buildings in good condition , a non - profit body was created , the Corporation du fort Saint - Jean . The " Campus du Fort Saint - Jean " then became a commercial and public site . The Corporation du Fort Saint - Jean leased some of its educational facilities to institutions such as the Université du Québec à Montréal ( UQÀM ) for their local programmes while also renting out other facilities for short - term events such as banquets , conventions and weddings . Moreover , the House of Commons ' Language School was established in the Massey Building , where many federal Members of Parliament came to improve their French . However , the site never completely lost its military educational vocation ; preparatory - year cadets and groups of officers continued to follow courses at Fort Saint - Jean . In 2008 , the military college was reopened and currently offers classes to preparatory , first - and second - year cadets , although it is no longer a degree - granting institution . However , CMR St - Jean remains a commercial site that is open to public , which is unique in Canada . There are both a museum and a multisport complex ( including an ice rink and a swimming pool ) located on - site . Fort Saint Jean Museum . Fort Saint - Jean Museum was founded in 1960 as a private collection of artifacts , military objects and historical documents . With the years , the museum expanded its collection and new offers several instructive exhibitions about the site ’ s rich military past and history . The Museum was first located in the Old Guardhouse built by the Royal Engineer between 1883 and 1889 , but was relocated in 2005 to the CMR ’ s old Protestant Church to better accommodate its exhibition and customers . The Musée du Fort Saint Jean has collected some 2588 pictures for an online photo album illustrative of the history of Collège militaire royal de Saint - Jean from 1952 to 1984 . Archaeology at Fort Saint Jean . In the early 1980s , Parks Canada led archaeological digs at Fort Saint Jean and discovered on that occasion the foundations of a part of the 1748 French fort and plenty of interesting artifacts of both the French and British Regimes . In collaboration with Fort Saint Jean Museum , the Royal Military College of Saint - Jean and Université Laval , a five - year long digging project ( 2009 – 2013 ) taking place in the summer at Fort Saint - Jean . Archaeology students for University Laval are doing excavations from mid - July to mid - August in order to find out more about the past of the site . The site ’ s features and historical buildings . A metal National Historic Site of Canada plaque at the main gate of the college describing the history of Fort Saint - Jean reads , The DeLery Building , an academic classroom building , was named after Gaspard - Joseph Chaussegros de Léry , a military engineer who built Fort Saint - Jean in 1748 . The Officer ’ s Mess , the La Galissonière Pavilion , and the Montcalm Pavilion are British buildings that were built in 1839 by the Royal Engineers . Escadron Richelieu uses Cartier Block and Pavillon Lahaie . Pavillons Vanier , DeLéry , Dextraze , Massey and the Old Mess are shared . The campus provides state - of - the - art technological support : library , well - equipped laboratories , ample supplies of learning materials , and Internet access .