On the wrong sideSourced
A border-defence fort turned out to be in Canada
In 1816 the United States began building a fort at the northern end of Lake Champlain. A new survey placed the site in Canada, halting construction. The abandoned structure acquired the nickname Fort Blunder. A border adjustment in 1842 allowed a new fort to be built on the same site.
The defence plan depended on knowing where the border actually was.
Summary / translation: Unbubly · CC BY-SA 4.0
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Fort Montgomery (Lake Champlain) · Wikimedia contributors
Fort Montgomery (Lake Champlain) ↗
Adapted, summarized and translated from the source. Adapted text is also available under CC BY-SA 4.0.
Reviewed: 2026-10-10