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.

Preston is a community in Cambridge, Ontario, Canada in the Regional Municipality of Waterloo, Ontario. Prior to 1973 it was an independent town, incorporated in 1915, but amalgamation with the town of Hespeler, Ontario, the city of Galt, Ontario and the village of Blair formed the new municipality of Cambridge. Parts of the surrounding townships were also included. No population data is available for the former Preston since the Census reports cover only the full area of Cambridge, though the combined population of the census tracts covering the majority of Preston reported a population of 20,008 as of the 2016 Canada Census. The first mayor of Cambridge was Claudette Millar.