Cambridge (2011 population 126,748) is a city located in Southern Ontario at the confluence of the Grand and Speed rivers in the Regional Municipality of Waterloo, Ontario, Canada. It is an amalgamation of the City of Galt, the towns of Preston and Hespeler, and the hamlet of Blair. Galt covers the largest portion of Cambridge, making up the southern half of the city. Preston and Blair are located on the western side of the city, while Hespeler is in the most northeasterly section of Cambridge.

Cambridge began as a composite city in 1973, when the City of Galt, Towns of Preston and Hespeler, and the hamlet of Blair were amalgamated.

There was considerable resistance among the local population to this "shotgun marriage" arranged by the provincial government and a healthy sense of rivalry had always governed relations among the three communities. Even today, though many residents will tell the outside world that they call Cambridge home, they will often identify themselves to each other as citizens of Galt or Preston or Hespeler. Each unique centre has its own history that is well documented in the Cambridge City Archives.

The first mayor of Cambridge was Claudette Millar, who at the time was one of the few female mayors and, at 35, the youngest mayor in Canada.

As Cambridge has developed and the open spaces between the original municipalities have been filled in, a fourth commercial core, entirely modern in its construction, has emerged. The Macdonald-Cartier Freeway Highway 401 runs through its midst.

On May 17, 1974, flooding on the Grand River was so intense it filled city streets with water to a depth of about four feet. Hundreds of businesses and homes were severely damaged.

Cambridge has been characterized by rapid growth in recent years. According to recent Economic Development estimates, the projected population for 2031 is 180,000.

According to the Canada 2006 Census, Cambridge is populated by people of a European ethnic background - 90.2%, mostly those of English (31,400), Scottish (20,625), Irish (19,040), German (14,110), Portuguese (10,685) and French (10,040) origins. Many Newfoundlanders (mostly from the Conception Bay and Bell Island area) have migrated to Cambridge, mostly due to the closure of the iron ore mines on Bell Island.

The city is largely Christian at 80.2%, followed by non-religious people who number 15%. Muslims, Hindus and other faiths make a little over 5% of the population. Over the last few years the numbers of Indians, Pakistanis and Afghanistanis moving in from other urban areas or immigrating from their respective countries, has doubled and tripled. Cambridge is also much younger than the national average. 21.6% of the population are under 14 years of age. Only 11% of the population is over 65, resulting in an average age of 35.2, slightly lower than the national average.