Fort Calgary was a North-West Mounted Police outpost at the confluence of the Bow and Elbow rivers in present-day Calgary, Alberta, Canada. Originally named Fort Brisebois, after the outpost's first commander, the outpost was renamed Fort Calgary in June 1876.

The outpost was built in 1875 as a part of the North-West Mounted Police (NWMP) larger effort to curtail American rum and whisky runners in the region, and to establish relationships with the Indigenous peoples of the territory. The palisades were removed in 1882 and the former fort was designated as a "district post". The NWMP used the expanded barracks there until 1914 when the site was sold to Grand Trunk Pacific Railway. The police buildings were demolished to make way for a rail terminal, although the site's significance was later recognized when it was named a National Historic Site in 1925.

In 1975, the municipal government of Calgary purchased a plot of land that included the National Historic Site and reopened it as Fort Calgary Historic Park in 1978. The historic park initially documented the NWMP role in the area, although its scope was expanded to focus on the Calgary's history in 1995. Reconstruction of several former buildings within Fort Calgary took place in the 1990s. In 2024, the Fort Calgary Historic Park was rebranded as The Confluence Historic Site and Parkland to better reflect the historical significance of the area.

The confluence of the Bow and Elbow River, where the fort was built, is on the traditional territory of the Niitsitapi (Blackfoot Confederacy; Siksika, Kainai, Piikani), the îyârhe Nakoda (Chiniki, Bearspaw, Wesley), the Tsuut'ina people and Métis Nation, Region 3, and has been a significant age-old gathering place.^{[citation needed]}

By the early 1870s, American whisky and rum runners were conducting trade with First Nations in the area. The illegal trade and American incursion prompted the government of Canada to create the North-West Mounted Police (NWMP) in 1873 to reassert Canadian sovereignty and curtail the whisky trade in the region. By 1874, the NWMP had captured or chased away most of the illegal traders, and had begun work on several forts in the area; believing that the lawlessness seen in the settlement of the American west was preventable if law enforcement was in place before settlers arrived into the area. After Fort Macleod was established, the whisky traders moved their operations further away from it. A decision was made to build an NWMP outpost at the midway point between Fort Macleod and Fort Edmonton in June 1875. "F" Troop, commanded by Éphrem-A. Brisebois, was tasked with establishing the outpost at the midway point.

The I. G. Baker Company arrived at the site in July 1875, having been hired to construct the NWMP outpost. The fort was initially planned to be located near present-day Holy Cross Centre, with an advanced detachment of "F" Troop marking a spot near the site. However, Brisebois elected to build the fort near the junction of the Bow and Elbow Rivers instead. Materials including spruce and pine were logged upstream and floated down to the site. The fort was originally bounded by a wooden palisade with several structures inside it; including a stables, barracks, guard room, and storage facilities. The fort was completed by December 1875, and cost the Canadian government C$2,476 to build. The outpost was initially known as the Bow River Fort until it was officially named Fort Brisebois in December 1875, after the commander of "F" Troop. However, Brisebois' superiors at NWMP headquarters had felt Brisebois misused his authority in naming the outpost and decided to rename the outpost Fort Calgary in June 1876. The name was recommended by James Macleod of the NWMP, who took the name from Calgary House in Scotland.

The outpost had inadequate heating and insulation after it was completed, resulting in poor living conditions for its garrison. Combined with Brisebois' poor leadership, the members of "F" Troop mutinied during the winter of 1875–76 and sent a delegation to the headquarters in Fort Macleod to list out complaints against the commander. Brisebois was not relieved immediately after that incident, although was eventually replaced by Lawrence Herchmer in August 1876.

The I. G. Baker Company incorporated the area around the fort as a part of its larger transportation network on the Whoop-Up Trail; and built a trading post and storehouse a few hundred metres away from the fort. The commercial opportunities provided by the transportation network also attracted the Hudson's Bay Company, who relocated their trading post at the Ghost River to the Elbow River across from Fort Calgary. Initially, the outpost also housed a mission of the Missionary Oblates of Mary Immaculate, although the mission later relocated upriver in 1875. By 1877, a permanent church was established at the I. G. Baker Company post. During the latter half of the 1870s, the area found itself as a stopover route for travellers going from Fort Benton, Montana to Fort Edmonton.