Fort Montgomery was a fortification built on the west bank of the Hudson River in Highlands, New York by the Continental Army during the American Revolution.

The strategic importance of the ability to control navigation along the Hudson River was obvious to both the Americans and the British from the outbreak of open hostilities.

A month after the first open armed conflict in Lexington, the Continental Congress resolved on May 25, 1775 to build fortifications in the Hudson highlands for the purpose of preventing the British from gaining control of the river and dividing the colonies.

It noted that "…a post be also taken in the Highlands on each side of Hudson’s River and batteries erected in such a manner as will most effectually prevent any vessels passing that may be sent to harass the inhabitants on the borders of said river…"[3] James Clinton and Christopher Tappan, both lifetime residents of the area, were sent to scout appropriate locations.

Fort Montgomery was located at the confluence of Popolopen Creek with the Hudson River near Bear Mountain in Orange County, New York.

The strategic importance of the opposite bank of Popolopen Creek was quickly realized, as it was an elevated cliff terrace with a full view of the Fort Montgomery site and could not be left undefended.

The Army also conceived a major engineering project to effectively blockade any naval traffic headed north on the river.