Four soldiers wearing the red uniform are posted in front of a door. An other soldier is looking at them.
Review of the troops at Fort Lennox
© Parks Canada

The inauguration of the first local railroad line (Saint-Jean-Laprairie, 1836) and the opening of the Chambly canal (Chambly-Saint-Jean, 1843) made the town of Saint-Jean the economic and military hub of the Richelieu River Valley. As a result, the strategic importance of île aux Noix declined substantially.

In 1837-1838, the rebellion by the Patriotes of Lower Canada brought about a resurgence of activity at île aux Noix. The island was used as a base of operations designed to crush the insurgents. Once the rebellion was over, fort Lennox became a military establishment of secondary importance. In 1858, the fort was used as an internment camp for young offenders. The 1860s, years coinciding with the American Civil War and its aftermath, saw a renewal of military activities on the island. The British left the island permanently in 1870.

Black and white picture of the door, the bridge, the ditch and the natural environment around Fort Lennox.
Fort Lennox, circa 1890
© National Archives of Canada / C-11528

Following the departure of the British army, the Canadian government decided not to reoccupy fort Lennox, since the Treaty of Washington provided a guarantee against any American threats for some time. The island was leased to farmers, who used it for pastureland. In 1899, fort Lennox was rented out to a certain Mr. Naylor, who operated it as a summer resort. In 1921, the Department of Militia and Defence transferred ownership of the island to the Department of the Interior. During World War II, fort Lennox was used as a camp for German Jewish refugees. From 1940 to 1943, around three hundred men were interned, first as prisoners of war, then as refugees from Nazi's persecutions.

The Historic Sites and Monuments Board of Canada designated fort Lennox as a historic site of national interest shortly after its own foundation in 1920. The island was declared a national historic park in 1940, but it was only in 1970 that the Canadian government began conservation and restoration of this impressive fortification in earnest.