After the American Revolution in the late 1700s, many English loyalists fled to Canada (primarily the Maritimes provinces and to Ontario) and continued the Georgian style as a statement of loyalty to Britain; a style the Americans were not rejecting due to the Revolutionary War. Perhaps the best example of this style is the Campbell House (1822) in Toronto.
Parliament in Ottawa
However numerous other styles from Europe also arrived during the 1800s, most particularly the "neo" styles, including the most visible today, the Neo-Gothic or Gothic Revival style. Most churches took this style, but so did many government buildings. St. Michael's Cathedral in Toronto (1845-1848) and later the Parliament Building (1850s; renovated and expanded since) in Ottawa were both built in this style.
The 1800s were also a time when westward expansion to the Pacific Ocean was a goal of the ethnic European people. As the railroad and people settled further and further west small homes were built in the prairies, not unlike the homes and churches of the early settlers. As this expansion continued most houses were small and simple in form and function and the churches tended to remain loyal to the European style.
Banff Springs Hotel
Due to this westward expansion though, a new style also emerged called the Chateau or Railroad Gothic style. As the railroad companies built to the west they also built massive hotels so their train guests would have housing along the journey. This massive and ornate hotels defined this style and are best represented by the Banff Springs Hotel (Banff, Alberta), the Chateau Lake Louise (in Alberta), and the Empress Hotel in Victoria, British Columbia.
Royal Ontario Museum
With the Industrial Revolution in the 1700s, new building technology, techniques, and materials were developed or perfected, giving architecture more flexibility. This led to modern architecture, which consists heavily of concrete and glass. Although these materials arrived earlier, the style didn't truly arrive until the late 1800s and early 1900s with the development of the skyscraper and the rapid upward growth of cities, beginning with the U.S. cities of Chicago and New York, then quickly spreading to Canada. Today every large city is riddled with buildings in this style, most particularly Toronto and Vancouver, although every major city from Halifax to Yellowknife has buildings of this type.
During the modern age, Quebec built numerous structures in this style as well, but also tried to incorporate these new materials into more cultural and historic designs. This is best represented by the Place Ville-Marie (1962), designed by architect I.M. Pei.
In more recent years post-modernism has dominated Canada. Toronto developed rapidly in the 1980s to the present so received many buildings in this style, including the Mississauga Civic Centre (1987; Mississauga is a suburb of Toronto), the CN Tower (Canada's National Tower), and the Royal Ontario Museum.