William Donald Dennison (January 20, 1905 – May 2, 1981) was a Canadian social-democratic politician that served in both the Ontario Legislative Assembly and finally as the City of Toronto's mayor. He served two nonconsecutive terms as a Member of Provincial Parliament (MPP) in the 1940s and early 1950s. After his provincial-level career, he focused on Toronto's municipal politics, holding offices as an alderman, member of the Toronto Board of Control, and finally as the city's mayor. He was the mayor from 1967 to 1972, winning two consecutive three-year terms. Prior to entering politics, he was a school principal and teacher. As of 2022, he was the last mayor of Toronto to be a member of the Orange Order. Background Dennison grew up on a farm in Renfrew County. He first left home at age 15 to work in the lumber camps of Northern Ontario. As a young man, he would trek west to Saskatchewan in the summers to earn money helping with the harvest and pitching grain. By night, he would educate himself by reading Little Blue Books. As a child and a young man he stammered to the point where he struggled to pronounce his name, although after several attempts to manage his stammering, first at a school in Kitchener and later at a school in New York City, he learned how to control it himself, opening his own School of Speech Correction. Politics UFO/CCF Dennison was a member of the United Farmers of Ontario in the 1920s, and became a member of the Co-operative Commonwealth Federation and its successor, the New Democratic Party. He was the CCF candidate in the Rosedale electoral district during the 1935 federal election: he placed third. He won a seat in the 1943 provincial election as the Ontario CCF Member of Provincial Parliament (MPP) representing St. David electoral district in downtown Toronto. He defeated Progressive Conservative candidate Roland Michener, a future Governor General of Canada. In the legislature, Dennison was an early environmentalist. As an early conservationist, in the 1940s, he tried to stop the de Havilland aircraft factory from polluting Black Creek. He also tried to force the government to stop a pulp and paper mill from polluting the Spanish River. In 1946 he personally planted 40,000 trees. Michener defeated Dennison in the 1945 provincial election, but Dennison regained the seat in the 1948 election. Dennison lost his seat for the