Highway 400A (Ontario)

Highway 400A was a 400-series highway in Canada. It was the Ontario Ministry of Transportation's internal designation for the 1.1-kilometre (0.7 mile) stretch of highway in Simcoe County which connects Highways 400 and 11. It is now part of Highway 11.

The stub was part of the original route of Highway 400, whose original terminus was an interchange at Crown Hill. At the same interchange, Highway 11 switched from its main highway routing to Penetanguishene Road into Barrie. However, when Highway 400 was extended northward toward Muskoka in the early 1980s, the extension was built 1.1 kilometres southwest of the interchange, so as to protect the northern segment of Penetanguishene Road. The construction thus left the short stub which was designated as 400A. Interestingly, Highway 11 is considered the "mainline" route, as traffic to and from the Highway 400 extension enters and exits at the right of the roadway.

The highway was never publicly signed as 400A; the northbound lanes were only ever signed as "To 11" and the southbound lanes as "To 400". There were no intermediate interchanges between the termini. At the time, it was considered by many to be an extra-long ramp connecting both routes.

With the restructuring of the provincial highway system in 1997, Highway 11's entire route south of the Crown Hill interchange was downloaded to the local municipalities. The Highway 11 designation was instead extended along the former 400A, and Highway 11's signed terminus is now the more southerly Highway 400 y-junction interchange.