The second largest mall in Canada, as well as the largest mall in Ontario.

Square One was built in 1973, one year before Mississauga became the city it is today. As was the case with many of the buildings in Mississauga at that time, the mall was almost completely surrounded by farm land. Today, Square One is surrounded by Mississauga's City Hall, as well as a large library and a bustling business district.

Square One currently boasts more than 360 stores, including four major department stores (Zellers, Sears, The Bay and Wal-Mart) and 40 restaurants and food vendors. The mall is also home to a Cineplex Odeon, a church, a blood donor clinic and a youth center.

A popular theory about the origin of the mall's name states that the mall was built on the first grid square planned by urban planners, hence 'Square One'.

Square One is also a central part of the Mississauga transit systems. Most bus routes start and finish at Square One's bus terminal.