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 716 km (445 mi) 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 535.7 km (332.9 mi) long; the western segment begins at Highway 4 north of London and extends 154.1 km (95.8 mi) to Georgetown, while the eastern segment begins at Donald Cousens Parkway in Markham and extends 381.6 km (237.1 mi) to Highway 417 in Ottawa.

King's Highway 40, commonly referred to as Highway 40, is a provincially maintained highway in the southwestern portion of the Canadian province of Ontario. The 91.4-kilometre (56.8 mi) route links Chatham and Sarnia via Wallaceburg, following close to the St. Clair River. The southern terminus is at Highway 401 south of Chatham, while the northern terminus is at Highway 402 in Sarnia. The portion of Highway 40 between Highway 401 and north of Wallaceburg is within the municipality of Chatham-Kent, while the portion north of there is within Lambton County.