Fort Henry was intended to be the linchpin in a new, extensive system of defensive works that would protect the confluence of these trading routes. Because the construction of the Rideau Canal went over budget, only the Fort and four Martello towers, spaced along the Kingston waterfront, were completed. Nonetheless, Fort Henry is the largest fortification west of Quebec city. The Fort alone cost 70,000 British pounds sterling to construct, which is the equivalent to approximately $35,000,000 in modern Canadian currency.
The Fort was abandoned by the British Army in 1870, and was garrisoned by Canadian troops until 1891. The fort subsequently fell into disrepair until 1936, where it was then restored under the direction of Ronald L. Way as a living history museum. The fort was first opened as a museum on the 1st of August 1938.