Ottawa is the capital city of Canada. It is located in the southern portion of the province of Ontario, at the confluence of the Ottawa River and the Rideau River. Ottawa borders Gatineau, Quebec, and forms the core of the Ottawa–Gatineau census metropolitan area (CMA) and the National Capital Region (NCR). As of 2021, Ottawa had a city population of 1,017,449 and a metropolitan population of 1,488,307, making it the fourth-largest city and fourth-largest metropolitan area in Canada.

Ottawa is the political centre of Canada and the headquarters of the federal government. The city houses numerous foreign embassies, key buildings, organizations, and institutions of Canada's government; these include the Parliament of Canada, the Supreme Court, the residence of Canada's viceroy, and Office of the Prime Minister.

Founded in 1826 as Bytown, and incorporated as Ottawa in 1855, its original boundaries were expanded through numerous annexations and were ultimately replaced by a new city incorporation and amalgamation in 2001. The municipal government of Ottawa is established and governed by the City of Ottawa Act of the Government of Ontario. It has an elected city council across 24 wards and a mayor elected city-wide, each elected using the first-past-the-post voting election system.

Ottawa has the highest proportion of university-educated residents among Canadian cities and is home to several colleges and universities, research and cultural institutions, including the University of Ottawa, Carleton University, Algonquin College, Collège La Cité, the National Arts Centre, the National Gallery of Canada; and numerous national museums, monuments, and historic sites. It is one of the most visited cities in Canada, with over 11 million visitors annually.