Cambridge is a city in the Regional Municipality of Waterloo, Ontario, Canada, located at the confluence of the Grand and Speed rivers. Th…Cambridge is a city in the Regional Municipality of Waterloo, Ontario, Canada, located at the confluence of the Grand and Speed rivers. The city had a population of 138,479 as of the 2021 census. Along with Kitchener and Waterloo, Cambridge is one of the three core cities of Canada's tenth-largest metropolitan area.