Donald Cameron MacDonald was a Canadian politician. Referred to in the media as the "best premier Ontario never had," he represented the provincial riding of York South in the Legislative Assembly of Ontario from 1955 to 1982. From 1953 to 1970 he was the leader of the social democratic Ontario section of the Co-operative Commonwealth Federation and its successor, the Ontario New Democratic Party.

York South was a provincial riding in Ontario, Canada, that was represented in the Legislative Assembly of Ontario from 1926 to 1999.