When 1912 came along Sault Ste. Marie was Incorporation as a City.
And six years later the city amalgamated with the town of Steelton.
By this time Sault Ste. Marie was really booming, as the market for the city's
steel and resources expanded rapidly.
In 1924 the Provincial Air Service was established here, and soon became known world wide as a centre for fire fighting technology and techniques. The "Group of Seven" painters came to the Algoma area from 1918-1923, including Lawren Harris, A.Y. Jackson, Franz Johnston, J.E.H. MacDonald and Arthur Lismer. They rented a boxcar and outfitted it like a cabin, which was shunted to sidings near choice painting locations on the Algoma Central, traveling on foot or by canoe through the wilderness from there.
In the 1950's the construction of the St Lawence Seaway increased the traffic into the Great Lakes and enhance the markets for the Sault's manufacturing. The sixties brought about the construction of Transportation-Canada Highway across Canada, and the construction of the International Bridge to link to the U.S. Interstate Highway system.
More history of Sault Ste. Marie