Oak Ridges—Markham is a provincial electoral district in Ontario, Canada, that has been represented in the Legislative Assembly of Ontario since the 2007 provincial election. Its population in 2006 was 169,645, with 136,755 electors, the highest of any riding in Ontario. It is the fastest growing riding in the province, having experienced a 52.5% increase in population from 2001 to 2006. The electoral district was created in 2004 52.5% from Oak Ridges, 30% from Markham, 13% from Vaughan—King—Aurora district and 4.5% from York North riding.