The National Capital Region (NCR) (Région de la capitale nationale), also known as Canada's Capital Region and Ottawa–Gatineau, is an official federal designation encompassing the Canadian capital of Ottawa, Ontario, the adjacent city of Gatineau, Quebec, and surrounding suburban and exurban areas. Despite its designation, the NCR is not a separate political or administrative entity and falls within the provinces of Ontario and Quebec.

Defined by the National Capital Act (1985), the NCR covers an area of 4,715 km (1,820 sq mi), straddling the Ottawa River, which serves as the boundary between Ontario and Quebec. This area is smaller than the Ottawa–Gatineau census metropolitan area (CMA), which spans 8,046.99 km (3,106.96 sq mi). Ottawa–Gatineau is the only CMA in Canada that crosses provincial boundaries.

The Algonquins are indigenous to Ottawa-Gatineau. The first European settlement in the region was led by Philemon Wright, a New Englander from Woburn, Massachusetts who, on March 7, 1800, arrived with his own and five other families along with twenty-five labourers to start an agricultural community on the north bank of the Ottawa River (Hull, Quebec) at the portage to the Chaudière Falls.

The National Capital Region was first specified by the National Capital Act (1985).

Ottawa is located in the sub-region of Southern Ontario called Eastern Ontario. Gatineau is located in southwestern Quebec. Although overall Ontario is west of Quebec, the boundary in this region is situated in such a way that Gatineau is north of Ottawa, and northwest of the city centre.

The National Capital Region is situated close to where the Canadian shield and the Saint Lawrence Lowlands intersect. The area has several major fault lines and small earthquakes do occur somewhat regularly, including the 2010 Central Canada earthquake that occurred in Quebec. The Gatineau Hills are the foothills of the Laurentian Mountains and located in the region.

The National Capital Region experiences a humid continental climate (Köppen Dfb), with four distinct seasons and is between Zones 5a and 5b on the Canadian Plant Hardiness Scale. In Ottawa, the average July maximum temperature is 26.6 °C (80 °F). The average January minimum temperature is −14.4 °C (6.1 °F). In Gatineau, the average July maximum is 26 °C (78.8 °F) while the average January minimum temperature is −15 °C (5 °F).

Most of the National Capital Region is recognized as a bilingual region for federal language-of-work purposes.

In addition, the City of Ottawa has a bilingualism policy, but is not declared "officially bilingual" (which would require amendments to the provincial law). About 19% of the population of the City of Ottawa has French as their first language, while 40% of the total population of the city declares itself fluent in both languages.

As for Gatineau, it is the most bilingual city in Canada, above Montreal. About 64% of the population is able to speak both English and French.

The National Capital Region includes the majority English-speaking (Ottawa) and majority French-speaking (Gatineau) cores. The metro region has a bilingual population of 496,025, an English-only population of 507,175, and a French-only population of 102,375.

In the 2021 Census of Population conducted by Statistics Canada, the Ottawa - Gatineau CMA recorded a population of 1,488,307 living in 604,721 private dwellings, a change of 8.5% from its revised 2016 population of 1,371,576. With a land area of 8,046.99 km (3,106.96 sq mi), it had a population density of 185.0/km (479.0/sq mi) in 2021.

Ottawa - Gatineau CMA 2021 population by census subdivision
Name	Province	Type	2021 Population	2016 Population	Change
Arnprior	Ontario	Town	9,629	8,795	9.5
Beckwith	Ontario	Township	9,021	7,644	18.0
Bowman	Quebec	Municipality	667	658	1.4
Cantley	Quebec	Municipality	11,449	10,699	7.0
Carleton Place	Ontario	Town	12,517	10,644	17.6
Chelsea	Quebec	Municipality	8,000	6,909	15.8
Clarence-Rockland	Ontario	City	26,505	24,512	8.1
Denholm	Quebec	Municipality	546	505	8.1
Gatineau	Quebec	Ville	291,041	276,245	5.4
La Pêche	Quebec	Municipality	8,636	7,863	9.8
L'Ange-Gardien	Quebec	Municipality	6,102	5,464	11.7
Lochaber	Quebec	Township	446	415	7.5
Lochaber-Partie-Ouest	Quebec	Township	926	856	8.2
Mayo	Quebec	Municipality	704	601	17.1
McNab/Braeside	Ontario	Township	7,591	7,178	5.8
Mississippi Mills	Ontario	Town	14,740	13,163	12.0
Mulgrave-et-Derry	Quebec	Municipality	461	369	24.9
North Grenville	Ontario	Municipality	17,964	16,451	9.2
Notre-Dame-de-la-Salette	Quebec	Municipality	841	727	15.7
Ottawa	Ontario	City	1,017,449	934,243	8.9
Pontiac	Quebec	Municipality	6,142	5,850	5.0
Russell	Ontario	Township	19,598	16,520	18.6
Thurso	Quebec	Ville	3,084	2,818	9.4
Val-des-Bois	Quebec	Municipality	920	865	6.4
Val-des-Monts	Quebec	Municipality	13,328	11,582	15.1
Total CMA	—	—	1,488,307	1,371,576	8.5

During the decade of 1990–2000, Ottawa was home to several very successful tech companies, including Nortel Networks, JDS Uniphase, and Newbridge Networks. High-tech employment doubled in five years to reach 80,000 by 2001. With Nortel failing to meet high earnings expectations and layoffs starting in 2002 in the wake of the dot-com bubble, the company started to decline, a devastating shock to the tech industry in Ottawa. Others described it as an 'anchor' for the industry in Ottawa, and an 'incubator' and that without it the Ottawa high-tech industry could not sustain itself.

By the mid 2000, other Canadian regions were competing for the title of Silicon Valley North. The term was being adopted to refer to the area between Toronto and Kitchener-Waterloo, which is home to Research in Motion (BlackBerry), and offices for Google, Adobe Inc., and Microsoft. With companies such as Shopify, Halogen Software, and Kinaxis Inc, all headquartered in Ottawa, as well as over 1,700 other technology companies, Ottawa still has a significant high-tech presence today.

The National Capital Commission (NCC) is a corporation established by the Canadian government in 1959 to manage federal buildings and land within the National Capital Region (NCR). While the NCR is not a separate political jurisdiction, the NCC has a mandate to develop the region into a source of pride and unity for Canadians by engaging in political, cultural, and land use planning matters that are typically powers reserved for the provincial government under the Constitution of Canada. In the Supreme Court of Canada case of Munro v. National Capital Commission, it was determined that the NCC has authority to be involved in zoning matters in the NCR.

In 2006, the NCC completed work on Confederation Boulevard, a ceremonial route connecting key attractions in the NCR on both sides of the Ottawa River. The NCC River House, originally constructed in 1914, underwent substantial restoration from 2019 to July 2023. It is located adjacent to the Ottawa River near the Sir George-Étienne Cartier Parkway.

The NCC reports to Parliament through the Minister of Heritage, and is governed by the National Capital Act. Its headquarters are in the Chambers Building on Elgin Street, between Queen and Sparks Streets.

The National Capital Region (NCR) has numerous attractions, including festivals, national museums, iconic buildings, sports, and entertainment. Ottawa is known for its examples of Gothic Revival architecture.

Annual events include the music festival Bluesfest, winter festival Winterlude, the Canadian Tulip Festival, Capital Pride, RCMP Musical Ride, Gatineau Hot Air Balloon Festival, Buskers festival, and the largest Canada Day celebrations in the nation.

The region hosts several national museums, such as the Canadian Museum of History, Canadian War Museum, Canadian Museum of Nature, Canada Science and Technology Museum, National Art Gallery, and Canada Aviation Museum.

Prominent buildings include Parliament Hill, the Prime Minister's home 24 Sussex Drive, the Governor General's home Rideau Hall, the Canadian Museum of History, the National Gallery of Canada, the Supreme Court of Canada, the Royal Canadian Mint, the American Embassy, and the National Library.

There are 29 National Historic Sites of Canada within the National Capital Region, including landmarks like the Former Almonte Post Office and Rosamond Woollen Mill in Almonte, the Gillies Grove and House in Arnprior, the Manoir Papineau in Montebello and the Symmes Hotel in the Aylmer sector of Gatineau.

The NCR is home to various sports teams, including the Ottawa Senators (NHL), Ottawa Redblacks (CFL), and Atlético Ottawa (CPL). The Ottawa 67's (OHL) and Quebec Maritimes Junior Hockey League (QMJHL).

Universities like Carleton University and the University of Ottawa compete in U Sports, with teams like the Carleton Ravens and Ottawa Gee-Gees achieving national recognition. Gatineau's Université du Québec en Outaouais offers a range of sports activities at its large sports center where you can practice a multitude of sports like Yoga, Zumba and more. Algonquin College has also won numerous national championships.

The National Capital Region (NCR) has several major freeways including the 417, Ontario Highway 416, Quebec Autoroute 5, Quebec Autoroute 50, Regional Road 174, and Highway 7 in Ontario.

The 417 is Ottawa's east–west commuter expressway. It begins at the Ontario-Quebec border (continuing the route of Quebec Autoroute 40), reaches the urban portion of Ottawa at the 417-174 split, bisects the urban area, and continues westward to just beyond the city boundary where it gives way to Highway 17 in Renfrew County.

The 416 starts at the 401 near the Ogdensburg-Prescott International Bridge and continues north for 75 km until it ends at the 417 in Ottawa's west end.

The freeway section of Highway 7 branches off the 417 in Ottawa's west end near Stittsville and is currently undergoing a 4-lane expansion to reach the eastern fringe of Carleton Place at McNeely Avenue.

Public transportation is handled by OC Transpo on the Ontario side, and the STO on the Quebec side. Together they serve a population over 1,130,761 and have an estimated annual ridership of over 113.2 million.

OC Transpo operates a light rail transit (LRT) system named the O-Train with two lines in operation. The O-Train Trillium Line is a north–south line using diesel-powered units and has just over 2 million riders per year. The Confederation Line links the western suburbs and the eastern suburbs via downtown, and uses electrically powered light-rail vehicles. The Confederation Line is 12.5 km long with 13 stations, 3 of which are underground in downtown Ottawa. There is a proposed LRT system in Gatineau that would connect with the Confederation and Trillium Lines in Ottawa.

Gatineau's bus transitway, the Rapibus, commenced operation in October 2013.

OC Transpo has about 1,050 buses which run on city streets and an expansive Transitway. The STO has around 300 buses that serve the Quebec side of the Ottawa River, some routes crossing into downtown Ottawa.

Ottawa Macdonald–Cartier International Airport serves as the primary international airport for the NCR. In 2023, it accommodated over 4 million passengers, ranking it as the sixth busiest airport in Canada and the second busiest in Ontario. The airport provides non-stop flights to various destinations in Canada, the United States, the Caribbean, and Europe. Additionally, it is a key component of some of the nation's busiest air routes, offering hourly flights to and from Montreal-Pierre Elliott Trudeau International Airport and Toronto Pearson International Airport.

The National Capital Region uses 613, 343, and 753 on the Ontario side of the Ottawa River, while 819, 873, and 468 are used on the Quebec side.

Previously, Ottawa and Hull operated as a single local calling area, with exchange protection measures to maintain seven-digit dialing between the two cities. However, with the implementation of ten-digit local dialing since 2006, this practice has ceased. Despite this, a "dual dialability" system remains for federal government numbers, allowing for seamless communication across the provincial border.

Three main daily local newspapers are printed in Ottawa: two English newspapers, the Ottawa Citizen and the Ottawa Sun, and one French newspaper, Le Droit.

Proposals have been made to separate the National Capital Region and establish it as a distinct capital district, similar to the District of Columbia or the Australian Capital Territory. These gained attention during periods when the Parti Québécois held power in Quebec, particularly due to the federalist inclination of the Hull/Gatineau area. However, any potential federal support waned after the 1995 Quebec referendum, where the predominantly federalist vote in Hull/Gatineau significantly influenced the outcome. Recent efforts for a separate capital district haven't gained momentum, with no active movement as of 2024.

• List of diplomatic missions in Ottawa
• Eastern Ontario
• Outaouais
• Southern Ontario

• Julie Harris (September 30, 2019). "National Capital Region - TheCanadianEncyclopedia.ca". The Canadian Encyclopedia. Retrieved February 28, 2022.

• National Capital Commission
• Canadian War Museum
• Canadian Museum of Civilization