[2] Fort George's large size was due to its original purpose as a supply depot, rather than as a true defensive fortification.

[3] However, after the Jay Treaty was signed, British forces were required to withdraw from U.S. territory, including Fort Niagara.

[4][note 2] In 1791, land was formally set aside to build new fortifications on the high ground adjacent to the Navy Hall at Niagara-on-the-Lake.

[4] In an attempt to negate this advantage, American forces built a battery on an elevated river bank opposite of Fort George.

[4] Tensions with First Nations and the U.S. government in the late 1790s prompted British forces to refortify the colony, including the fort itself.

[9] After Brock's death at Queenston Heights, he was buried in a military funeral at Fort George's northeast bastion.

[11] Two days later, an American landing force of 2,300 troops disembarked in four waves approximately 3 kilometres (1.9 mi) from Fort George, on the shoreline of Lake Ontario under the cover of cannonade fire.

[11][12] First Nations warriors under John Norton covered the British retreat, although the Americans made no real effort to pursue them.

[13] American forces were able to prevent the destruction of a substantial portion of what remained of the fort, having arrived quickly enough for a U.S. artillery captain to extinguish one of the magazine fuses.

[15] In addition to rebuilding the earthwork ramparts, they also repaired the palisades, and added entrenchments near the northeast bastion and towards the river.

[10] Although the fort was intended to act as a bridgehead for an American invasion of the peninsula, the American military was forced to reconsider its invasion plans after facing several setbacks; including disease, increased desertion rates, continued risk of ambush outside the confines of the encampment, and a British advance towards the area after the battles at Stoney Creek, and Beaver Dams.

[15] Shortly after reoccupying the fort, the British began working on building a temporary barracks, officers' quarters, guardhouse, and another magazine.

[10] In 1817, American president James Monroe visited the Canadian side of the Niagara River during a goodwill trip, and was entertained by British officers at the fort.

[4] During the same period, work on Butler's Barracks was undertaken southwest of the fort, and out of range of the batteries on the American side of the river.

[22] In 1828, the headquarters of British Army centre division was formally moved to York, with the fort reportedly only made up of a few "wooden decaying barracks".

[23] During this period, several buildings were converted for other uses; with the officers' quarters incorporated into a farmhouse, the stone gunpowder magazine used for storing hay, and the property itself used as a grazing field for cattle.

[23] By the 1880s the bastions and the gunpowder magazine were in poor condition, portions of the fort were being used as farmland, with only the officers' quarters occupied by a custodian.

As the golf club's membership was predominantly made up of American residents summering in the area, the proposal was subject to criticism from local and Toronto-based newspapers that published nationalistic editorials critical of the proposal; describing it as a "desecration of sacred heroic sites as [selling out] to Sabbath-breaking Americans".

[25][26] During the mid-1930s, the Department of National Defence accepted an offer from the Niagara Parks Commission, where the commission would reconstruct and restore Fort George, Fort Mississauga, and the Navy Hall, in return for a 99-year lease on all three properties for C$1 per year; although the department reserved the right to reclaim the properties after providing six-months notice.

[27] The fort reconstruction was completed in 1939 with the installation of its wooden gates, although its visitor centre remained under construction for several months after.

[27] The Niagara Parks Commission operated the fort as a museum, exhibiting military artifacts in the reconstructed blockhouses.

[27] In 1969, the lease with the commission was prematurely ended when the property was transferred from the Department of National Defence to Parks Canada.

[29] From 2009 to 2010, several archaeological digs were conducted to ascertain the landscape of the fort, as well as excavate artifacts left behind by soldiers during the war.

[43] A drainage system was required to drain the moisture collected from the ravine shortly after the magazine's completion, in order to preventing the floor boards from rotting.

[43] The ramparts of the fort were made up of irregular earthworks consisting of six bastions, each framed with timber and connected by a line of picketing.

[27] Because the fort was designed as a supply depot and not a true defensive fortification, the earthwork's bastions were poorly positioned, with a lack of interlocking lines of fire creating areas of vulnerability at certain parts of the ramparts.

[3] Attempts to rectify these deficiencies were made prior to the War of 1812, when Isaac Brock instructed that the fort's size be reduced, by abandoning the southern ramparts and erecting palisades at the new defensive line.

[48] During the late 1780s and early 1790s, the building was intermittently used by the lieutenant governor of Upper Canada, John Graves Simcoe as a private residence.

After the Erie and Niagara Railway line closed, process of reconstruct the building at its original location was undertaken.

[53] A number of its exhibits focus on lieutenant governor Simcoe, as well as the Provincial Marine, the maritime equivalent of the Canadian militia.