Fort Niagara stands at the mouth of the Niagara River where it meets Lake Ontario, making it one of the most strategically important military locations in North America. The site has been occupied for centuries, first by Native American nations who recognized its importance as a gateway between the Great Lakes and the interior of the continent. In 1678, French explorer Rene Robert Cavelier Sieur de La Salle established Fort Conti nearby to support his exploration of the Great Lakes. Although that early fort was short-lived, the French returned and built a more permanent stone fortress known as the Castle in 1726. Today, it remains one of the oldest surviving buildings in the Great Lakes region.

Throughout the early eighteenth century, the French used Fort Niagara to protect the fur trade and maintain control over transportation routes linking Canada with the Ohio Valley and the western frontier. The fort became a center of commerce, diplomacy, and military operations. Soldiers, traders, missionaries, and Native American allies regularly passed through its gates, making it one of the busiest frontier outposts in New France.

During the French and Indian War, Fort Niagara became a major objective for the British. In 1759, British forces, assisted by colonial troops and Native American allies, laid siege to the fort. After weeks of bombardment and the death of the French commander during an attempted relief effort, the French surrendered. The British occupation marked a turning point in the struggle for control of North America, helping shift the balance of power away from France.

The fort continued to serve an important military role during the American Revolution. Although American forces never captured it, the British used Fort Niagara as a base for military operations along the frontier and as a refuge for Loyalists fleeing the fighting. During the War of 1812, the fort was briefly captured by American troops before being retaken by the British in a surprise nighttime assault. Following the war, it was permanently transferred to the United States and remained an active military installation for generations.

Over the nineteenth and twentieth centuries, Fort Niagara evolved from a frontier fortress into a modern military post. New barracks, officers' quarters, and defensive structures were added while preserving many of the original colonial buildings. Today, the fort serves as a museum and historic landmark where visitors can explore centuries of military history. Its remarkably preserved architecture and dramatic location overlooking the Niagara River make it one of the finest surviving examples of colonial military engineering in North America.