Fort Lennox, Military museum and national historic site on Île aux Noix, Quebec, Canada.

Fort Lennox occupies most of Île aux Noix, an island in the Richelieu River about twelve kilometres from the Canada-U.S. border. The British army built the present fortification between 1819 and 1829 to plans by military engineer Gustavus Nicolls, placing most of the works on the south side of the island after razing the earlier French fort and redoubts. Restored stone buildings and defence works stand within a star-shaped, water-filled moat.

The British built the fort between 1819 and 1829 in response to military tensions with the United States and the need to secure the border region. Its construction marked an important phase in Canada's defense strategy at that time.

The fort displays military equipment and furnished rooms that show how British soldiers lived and worked during their time here. These spaces offer a glimpse into daily life at a 19th-century remote garrison.

A short ferry ride of about five minutes takes visitors from the welcome center to the island where the fort stands. Guided tours are offered during operating hours and help visitors understand the layout and historical details of the site.

The island's name predates the fort: Samuel de Champlain noted it in 1609 for its many butternut trees. In 1753 settler Pierre Jourdanet agreed to farm it for eight years without felling the trees, paying an annual rent of a pot of nuts to the seigneur's house in Montreal.