Which fortress in Quebec City is the largest British-built fortress in North America?

The Citadelle of Quebec is the largest British-built fortress in North America. Perched atop Cap Diamant, it commands Quebec City and the St. Lawrence River approach.

The modern star-shaped fortress was constructed between 1820 and 1850 after the War of 1812, when Britain strengthened the defenses of British North America against a possible American attack. Its design reflects the principles of French military engineer Vauban, while parts of the site incorporate earlier French fortifications.

The British garrison left in 1871, after Canada assumed responsibility for its own defense. The Citadelle remains an active military installation, serving as the headquarters of the Royal 22nd Regiment and as the secondary official residence of Canada's governor general.

It is often confused with Château Frontenac, the famous hotel nearby, or with Quebec City's broader fortified walls. The Citadelle is one component of the city's historic defenses, which helped Old Quebec become a UNESCO World Heritage Site in 1985. The site also hosted the secret 1943 Quebec Conference involving Winston Churchill, Franklin D. Roosevelt, and Canadian Prime Minister William Lyon Mackenzie King.