The Regional Municipality originally consisted of the Cities of Ottawa and Eastview, the Villages of Rockcliffe Park, Richmond and Stittsville, and the Townships of Torbolton, Fitzroy, Huntley, March, Goulbourn, Nepean, Osgoode, Marlborough, North Gower, Gloucester and Cumberland.

This included mass transit, policing, arterial roads, sewage, water, social services, garbage collection and Regional planning.

Periodical reorganization (e.g. rural townships acquiring city status, as in 1974 and 1978) did not impede the process.

[1] Ottawa thus became in sheer area one of the largest municipalities in Canada, roughly 65 kilometres by 32, much of this farmland, although 90 per cent of the population live in urban concentrations.

Generally in Ontario regional government reforms of the 1990s were sometimes mistrusted as preparation for eventual creation of unified "mega-cities", but this was not before 1999 a topic of local political anxiety in Ottawa-Carleton.