Ontario Highway 73

King's Highway 73
Route information
Maintained by the Ministry of Transportation of Ontario
Length	38.9 km[1] (24.2 mi)
Existed	August 25, 1937[2]–January 1, 1998[3]
Major junctions
South end	Colin Street, Port Bruce
Major intersections	Highway 3 – Aylmer  Highway 401
North end	County Road 29 (Hamilton Road) – Dorchester, Ingersoll
Location
Country	Canada
Province	Ontario
Highway system
Ontario provincial highways Current Former 400-series
← Highway 72 → Highway 77
Former provincial highways Highway 74  →

King's Highway 73, commonly referred to as Highway 73, was a provincially maintained highway in the Canadian province of Ontario. The route began in Port Bruce and progressed north through Aylmer, encountering Highway 401 immediately before terminating east of Dorchester. The route was established in mid-1937, remaining unchanged for nearly six decades before being transferred to Elgin County and Middlesex County in 1997 and 1998. Today the route is known as Elgin County Road 73 and Middlesex County Road 73.