Fort George was built by the British Army after Jay's Treaty (1796) required Britain to withdraw from Fort Niagara. The new fort was completed in 1802 and became the headquarters for the British Army and the local militia. Fort George was captured by U.S. forces in May 1813 at the Battle of Fort George. The American Army used the fort as a base to invade Upper Canada, but were repelled at the Battles of Stoney Creek and Beaver Dams. The fort was retaken by the British Army in December of that year after U.S. forces abandoned the British side of the river.
The fortification was used by the Canadian Army as a military training base during the First World War and through the Second World War under the name Camp Niagara. The grounds were eventually abandoned by the military in 1965.
The site is now a National Historic Site of Canada, maintained by Parks Canada. The fort is open to visitors from April to October. The staff maintains the image of the fort as it was during the early 19th century, with period costumes, exhibits, and displays of that time. They train summer students in the infantry tactics and firing drills of the 41st regiment from the War of 1812. They also have the 41st Fife and Drum Corps which provides an example of how the fife and drums were used.
Every year, reenactors from both the United States and Canada meet on and near the grounds of the fort and reenact the battle that took place nearly two hundred years ago. This has taken place since 1984 and has grown from a small group of 300 "troops" to over 1800.
The grounds surrounding the fort and the commons adjacent to the fort provided the site for the 8th World Scout Jamboree held in August 1955.
Fort George National Historic Site is one of a handful of sites managed under the administrative name "Niagara National Historic Sites" by Parks Canada, within the National Park System.
The television show The Girly Ghosthunters paid a visit to the fort to investigate any paranormal activity that was allegedly documented there. The episode was shown as the second, of thirteen, episodes of the show in 2005.