Dundas Street is a major historic arterial road in Ontario, Canada. The road connects the city of Toronto with its western suburbs and several cities in southwestern Ontario. Three provincial highways—2, 5, and 99—followed long sections of its course, although these highway segments have since been downloaded to the municipalities they passed through. Originally intended as a military route to connect the shipping port of York to the envisioned future capital of London, Ontario, the street today connects Toronto landmarks such as Yonge–Dundas Square and the city's principal Chinatown to rural villages and the regional centres of Hamilton and London.

King's Highway 2, commonly referred to as Highway 2, is the lowest-numbered provincially maintained highway in the Canadian province of Ontario, and was originally part of a series of identically numbered highways which started in Windsor, stretched through Quebec and New Brunswick, and ended in Halifax, Nova Scotia. Prior to the 1990s, Highway 2 travelled through many of the major cities in Southern Ontario, including Windsor, Chatham, London, Brantford, Hamilton, Burlington, Mississauga, Toronto, Oshawa, Belleville, Kingston and Cornwall, and many other smaller towns and communities.