Ontario Highway 7  King's Highway 7, commonly referred to as Highway 7 and historically as the Northern Highway, is a provincially maintained highway in the Canadian province of Ontario. At its peak, Highway 7 measured in length, stretching from Highway 40 east of Sarnia in Southwestern Ontario to Highway 17 west of Ottawa in Eastern Ontario. However, due in part to the construction of Highways 402 and 407, the province transferred the sections of Highway 7 west of London and through the Greater Toronto Area to county and regional jurisdiction. The highway is now long; the western segment begins at Highway 4 north of London and extends to Georgetown, while the eastern segment begins at Donald Cousens Parkway in Markham and extends to Highway 417 in Ottawa. Highway 7 was first designated in 1920 between Sarnia and Guelph and extended to Brampton the following year. Between 1927 and 1932, the highway was more than doubled in length as it was gradually extended eastward to Perth, where Highway 15 continued to Ottawa. In the early 1960s, that section of Highway 15 was renumbered as Highway 7. In that same decade, the Conestoga Parkway through Kitchener and the Peterborough Bypass were constructed. During the 1970s and 1980s, many sections of Highway 7 were widened from the initial two lane cross-section to four or six lanes. Within part of York Region, the route was upgraded to a limited-access expressway in preparation for the construction of Highway 407. Soon thereafter, that new tollway would act as justification for transferring the section of Highway 7 through the Greater Toronto Area (GTA) to regional governments. In the west, the construction of Highway 402 between Sarnia and London provided an uninterrupted alternative to Highway 7, resulting in the transfer of the section west of Highway 4. A third transfer took place in Peterborough, briefly separating the route into three discontinuous segments, but has since been rectified by renumbering a section of Highway 7A. From 2007 to 2012, the section of Highway 7 between Carleton Place and Ottawa has been widened to a divided freeway. In addition, work is underway to extend the Conestoga Parkway to New Hamburg as well as to build a new freeway between Kitchener and Guelph. The western segment of Highway 7 travels from Elginfield in Middlesex County in the southwest to the Halton - Peel border at Norval near Brampton; a distance of .