1939 to 1975
Gatineau was incorporated in 1939. From 1939 to 1975, the City of Gatineau encompassed a very small area compared to its current borders. Old Gatineau consisted of the area north of the Ottawa River opposite Kettle Island. Its western border was at present day Boulevard de la Cité and its eastern border went through present day Parc du Lac-Beauchamp. Its northern border was Boulevard Saint-René, but it was extended northward as the city expanded.

1975 to 2002
Prior to January 1, 2002, there were five cities on the Quebec side of the Ottawa River: Hull, Gatineau, Aylmer, Buckingham, and Masson-Angers. The former City of Gatineau was the largest of these municipalities, both in area and population.

The former City of Gatineau was itself the product of an amalgamation on January 1, 1975, when the municipalities of Gatineau, Pointe-Gatineau, Touraine, Templeton, Templeton-Ouest and Templeton-Est were merged in an effort to improve municipal services and coordinate urban growth. Before Bill 170, they were part of the Communauté Urbaine de l'Outaouais supra-regional organization.[3] With the 1975 amalgamation, Gatineau became the largest city in the Outaouais. Despite the 1989 separation of the Cantley area from the (now former) City of Gatineau, Gatineau remained the fifth largest municipality in Quebec by population, behind Montreal, Laval, Quebec City and Longueuil.