Chambly (shäNblēˈ) [key], city (1991 pop. 15,893), S Que., Canada, on the Richelieu River, E of Montreal. Chambly Fort was built in 1665 and was a strategic point in the defense of New France against the British and the Iroquois. The British captured it in 1760. It was seized by the invading Americans in 1775 and burned when they withdrew in 1776. The partially restored fort is a national historic site.