History of King's Highway 6A:
King's Highway 6A was a short highway which once connected Highway 2 (York Boulevard) to Highway 6 in the City of Burlington. The highway was created in the early 1970s, when an existing section of Highway 6 was reportedly renumbered as Highway 6A. Up until the early 1970s, the official route of Highway 6 followed York Boulevard (Highway 2) north from Downtown Hamilton. At the small community of Wolfe Island west of Aldershot, Highway 6 turned north from Highway 2 towards Guelph via Plains Road. Mileage logs produced by the Ministry of Transportation and Communications (MTC) after 1971 indicate that the official route of Highway 6 was changed so that it overlapped with Highway 403 between Wolfe Island and the York Boulevard Interchange north of Downtown Hamilton. The old route of Highway 6 via Plains Road became Highway 6A, while the former overlapped route of Highway 2 & Highway 6 via York Boulevard was discontinued.
It is not certain if this route was actually signed with Highway 6A route markers. Given its short length, it is quite possible that Highway 6A was merely signed with "TO 2" and "TO 6" trailblazer route markers. If this route was indeed signed as Highway 6A, it would have been the shortest posted King's Highway designation to ever exist in Ontario. Highway 6A was fairly short-lived. The last reference to the Highway 6A route number was in an MTC document dated 1976. However, the former route of Highway 6A (Plains Road West) was retained in the provincial highway network until the early 1980s, most likely as an unposted 7000-series route. Ownership of Plains Road West was transferred from the province to the City of Burlington, effective June 30, 1982.