Mississauga is a city in the Canadian province of Ontario. Situated on the northwestern shore of Lake Ontario in the Regional Municipality of Peel, it borders Toronto (Etobicoke) to the east, Brampton to the north, Milton to the northwest, and Oakville to the southwest. With a population of 717,961 as of 2021, Mississauga is the seventh-most populous municipality in Canada, third largest city in Ontario, and second-most populous in the Greater Toronto Area (GTA) after Toronto itself. However, for the first time in its history, the city's population declined according to the 2021 census, from a 2016 population of 721,599 to 717,961, a 0.5 per cent decrease.