Forming an irregular pentagon, the fort (1865-72) stands atop Pointe-Lévis, the highest point on the south shore of the St. Lawrence. It is the sole vestige of three such forts built to protect Quebec City from possible American attack after the threat of the American Civil War and from the Fenian Raids. The fort is composed of a series of massive earthen ramparts with a tall embankment protecting the casemates, ditches and vaulted tunnels leading to the caponiers-stone and brick structures armed with small cannon.