Fort Montgomery was a massive stone fortification built on the Northwest arm of
Lake Champlain at Island Point in the town of Rouses Point, NY. The fort was built in 1818 to protect against an attack from British Canada like that which led to the
Battle of Plattsburg in 1814. Due to an oversight, the fort was inadvertently built on the Canadian side of the border leading to the better known name of
Fort Blunder.
The first fort was apparently quickly removed. A second Fort Montgomery was built in the 1840s on American soil a short distance South of the original site.