Ottawa is the capital of Canada, the second largest city in the Province of Ontario, and the fourth largest city in the country. Located in the Ottawa Valley, the city lies in the eastern portion of Southern Ontario on the Ottawa River, a major waterway forming the local boundary between the provinces of Ontario and Quebec.

Ottawa is connected by several bridges to its Quebec neighbour on the shores of the Ottawa River — the city of Gatineau. The two cities and surrounding area are designated the National Capital Region (NCR). Though governed by separate municipal governments, the federal lands within the region are administered by the National Capital Commission (NCC), a federal crown corporation charged with the responsibility of planning and managing the federal government's interests in the NCR.

In 2006, the city of Ottawa had a population of 812,129, making it the fourth-largest municipality in the country and second-largest in Ontario. The Ottawa-Gatineau metropolitan area had a 2006 population of 1,130,761, making it the fourth-largest census metropolitan area (CMA) in Canada. The National Capital Region which encompasses Ottawa, Gatineau and surrounding suburbs and towns has an estimated population of 1,451,415. In 2009 Ottawa-Gatineau's population was estimated at 1,220,674, making it the fifth-largest CMA in Canada. In 2010, Ottawa had the 2nd highest quality of living of any city in the Americas, and 14th highest in the world according to the "Mercer Human Resource Consulting Quality of Living Survey". It was also considered the 3rd cleanest city in the world by Mercers 2010 eco-city ranking.