History of King's Highway 12B (Port McNicoll):
This short business route began at the original Highway 12 Junction (at today's Triple Bay Road), and entered Port McNicoll along First Street (today's Talbot Street). The highway ended at the intersection of First Street and First Avenue, although the provincially-owned section of Highway 12B ended at the Port McNicoll boundary at Ninth Avenue. Thus, roughly half of the highway's total length was in fact under municipal jurisdiction.
The history of the Port McNicoll Cut-Off Highway dates back to the late 1930s. A Preliminary Route Plan was prepared on April 29, 1937, showing a proposed extension of the King's Highway from Highway 12 easterly to Port McNicoll. The Department of Highways of Ontario (DHO) acquired the route on April 13, 1938, when the road to Port McNicoll was assumed as a King's Highway by the province. It is not certain if the route was initially signed as Highway 12B upon assumption in 1938. It is quite possible that the route was initially an unmarked King's Highway, with the Highway 12B designation applied later. The route is shown in DHO Mileage Tables from the 1960s and early 1970s as Highway 12B. The highway was 1.9 km in length, including the section owned by the Village of Port McNicoll. The highway was decommissioned in 1978, after a new Highway 12 Bypass was built that completely bypassed Port McNicoll. The Port McNicoll Business Route was decommissioned as a King's Highway, when the assumed portion of Highway 12B was transferred to the Township of Tay effective November 22, 1978. Four other Highway 12B Business Routes have existed over the years in Orillia, Coldwater, Gamebridge and Victoria Harbour.