Originally, Highway 7 extended as far west as Sarnia, remaining as a provincial highway for some time after the extension of
Highway 402 to London. At Warwick, Highway 7 crosses Highway 402, west of that point these routes ran parallel to each other for 40 km (both roads never being further than 2 kilometres apart) until
Highway 40. Upon entering the Sarnia city limits from the east on Highway 7, drivers encountered a plethora of motels and restaurants, the
Sarnia Airport, and attractions such as Hiawatha Racetrack and Waterpark, earning the stretch between Modeland Road and Airport Road the nickname of the "Golden Mile". The interchange with
Highway 40 marked the former western terminus of Highway 7, thereafter the road continues as Exmouth Street as the opposing carriageways merge and follow an S-curve before passing
Lambton Mall. Since being downloaded to municipal authorities, the former highway is now known as
Lambton County Road 22 (London Line) and
Middlesex County Road 7 (Elginfield Road). The two highways travel east
concurrently for , passing through the town of
Shakespeare as it travels in a straight line through farmland. Southwest of New Hamburg, the route curves northeast into
Waterloo Region, eventually widening into the four-lane Conestoga Parkway east of Nafziger Road. It follows this divided
freeway past interchanges at
Waterloo Regional Road 51 (Foundry Street) south of
Baden,
Waterloo Regional Road 12 (Queen Street/Notre Dame Drive) south of
Petersburg, and
Waterloo Regional Road 70 (Trussler Road) north of
Mannheim, where it enters Kitchener and becomes surrounded by residential subdivisions. Within Kitchener, Highway 7 encounters interchanges at
Waterloo Regional Road 58 (Fischer-Hallman Road)(at which point it widens to six lanes),
Waterloo Regional Road 28 (Homer Watson Boulevard),
Waterloo Regional Road 53 (Courtland Avenue),
Waterloo Regional Road 15 (King Street)/Highway 8 (at which point it widens to eight lanes),
Waterloo Regional Road 14 (Ottawa Street) and
Waterloo Regional Road 55 (Victoria Street). The Highway 8 concurrency ends at the King Street interchange, with it diverging southeast onto the
Freeport Diversion. Highway 7 exits at Victoria Street (four-lane arterial) while the parkway continues north into Waterloo as
Highway 85. Highway 7 exits Kitchener after crossing the
Grand River, where it enters farmland again for the brief journey to Guelph along Victoria Street and Woodlawn Road. Midway between the two cities, the route enters
Wellington County. Within Guelph, it meets
Highway 6 at the northern end of the Hanlon Expressway. The two routes travel southeast along the expressway to
Wellington County Road 124 (Wellington Street, former
Highway 24), where Highway 7 branches northeast into downtown Guelph. It exits the city along York Road after crossing the
Speed River, travelling parallel to and south of the
Goderich–Exeter Railway. At
Rockwood, the highway enters
Halton Region (and officially the
Greater Toronto Area) and begins to zig-zag through several communities in
Halton Hills. These include
Acton, where the route intersects former
Highway 25, and
Georgetown. Just east of Norval, the western section of Highway 7 ends at the Halton–
Peel boundary.
Downloaded Peel-York segment for
Viva buses running down its centre The downloaded section of Highway 7 continues into
Brampton as
Peel Regional Road 107 as it enters the heavily urbanized part of the GTA. Now named
Bovaird Drive, although this name has not been applied as of 2025. , opening on June 20, 2016.
Eastern segment The eastern segment of Highway 7 runs from
Donald Cousens Parkway (York Regional Road 48) in Markham to Highway 417 in Ottawa, a length of . Between
Brooklin and north of
Sunderland, Highway 7 assumes a north–south routing and is
concurrent with Highway 12. The section from Sunderland to the eastern terminus of the highway is designated as part of the
Central Ontario Route of the
Trans-Canada Highway. Travelling east from Donald Cousens Parkway, Highway 7 exits the urbanized portion of Markham and the GTA and enters the
Greenbelt, a large tract of land north of the GTA restricted from development. It curves north at the community of Locust Hill along an alignment that eliminated a jog, then curves back to the east as it crosses into
Durham Region. It travels north of and parallel to Highway 407 to
Brougham, curving to cross the former eastern terminus of the freeway near Brock Road (Durham Regional Road 1). East of the Highway 407 overpass, Highway 7 widens to four lanes and curves around the community of
Greenwood and the hill that it stands on. The route crosses the northern end of
Pickering, entering
Whitby at Lake Ridge Road (Durham Regional Road 23). Between Lake Ridge Road and Highway 12, the route was rebuilt for the new Highway 407E and
West Durham Link, with an overpass constructed at Cochrane Road. East of that, the route enters Brooklin and meets Highway 12. Highway 7 and Highway 12 travel north concurrently from Brooklin through Durham Region to Sunderland. At Sunderland, Highway 7 departs to the east with the Trans-Canada Highway designation, officially leaving the Greater Toronto Area and entering the City of
Kawartha Lakes. Despite its name, the highway passes through a mostly-rural landscape in Kawartha Lakes, bypassing south of
Lindsay in the middle of the "city" along a brief concurrency with
Highway 35. East of Lindsay, the route meanders southeast towards
Peterborough, encountering the divided freeway,
Highway 115, southwest of the city. The two routes travel east concurrently along the southern edge of Peterborough. Highway 115 and the divided freeway end at Lansdowne Street, onto which Highway 7 turns. , in the City of
Kawartha Lakes The segment between Peterborough and
Perth was built in the 1930s during the
Great Depression, as a
public works employment project. It was constructed parallel to a
CP Rail corridor (now abandoned east of Peterborough) that was built in the 1880s, and used hand-power to dig and build the road whenever possible. From Peterborough to Norwood, the route travels in a straight line through the
Peterborough Drumlin Field, connecting to the southern terminus of
Highway 28 and crossing the Indian River while otherwise passing through farmland. At
Norwood the route suddenly begins to meander as it approaches the undulated
Canadian Shield. The section east of
Havelock to Perth, unlike the rest of the highway, travels through a relatively isolated area, with few services or residences along the route outside of the several towns that it connects. In contrast to the surroundings west of there, this section is located in dense forest with numerous lakes and
muskeg dotting the landscape. It services the villages of
Marmora, where it connects with the northern terminus of former
Highway 14,
Madoc, where it intersect
Highway 62,
Actinolite, where it meets the northern terminus of
Highway 37, and
Kaladar, where it intersects
Highway 41. East of Kaladar, Highway 7 begins to serve
cottages along the shores of several large lakes that lie near the highway. It intersects the northern terminus of former
Highway 38 near
Sharbot Lake and later passes south of
Maberly before exiting the Canadian Shield and reentering farmland. On the outskirts of Perth, the route meets former
Highway 43 and curves northward. It travels around the western and northern shorelines of
Mississippi Lake before passing directly south of
Carleton Place. Just east of there, Highway 7 widens into a four-lane freeway for the remainder of the distance to Highway 417. This section, completed by early 2012, was built by "twinning" the existing two-lane highway with a second parallel carriageway to serve as the eastbound lanes. Highway 7 ends at a trumpet interchange with Highway 417, where drivers can proceed east to
Ottawa or north to
Arnprior. ; this section passes through the sparsely developed terrain of the
Opeongo Hills. == History ==