History of Secondary Highway 612 (#2):
The Secondary Highway 612 designation was used for a second time to mark a local highway in the Districts of Parry Sound and Muskoka starting in 1960. The route of Highway 612 began at Highway 103 (later Highway 69) south of Foot's Bay and connected to Highway 69 north of MacTier. This road through MacTier had previously served as a former route of Highway 69 up until 1956, when it was bypassed by the new Trans-Canada Highway route of Highway 69 (the MacTier Diversion). Accordingly, the Department of Highways of Ontario's (DHO's) acquisition of Highway 612 was rather unusual, as some sections of the former Highway 69 alignment were already back under municipal jurisdiction by the time the Highway 612 designation was introduced in 1960.
Highway 612 was first depicted on a Preliminary Assumption Plan prepared by the DHO in June, 1960. The plan showed the proposed assumption of the MacTier Road (Old Highway 69) from the Highway 103 Junction northerly through MacTier to the Muskoka-Parry Sound District Boundary. After this former section of Highway 69 through MacTier had been bypassed by the new Trans-Canada Highway in 1956, jurisdiction of the old highway was transferred to the township. The section of Old Highway 69 through the District of Parry Sound had been retained in the provincial highway system as an unnumbered provincial highway, merely known as "Old Highway 69". Both this assumed section of Old Highway 69 in the District of Parry Sound and the non-assumed section of the MacTier Road (Old Highway 69) which ran through the District of Muskoka were collectively designated as Secondary Highway 612 by an Order-in-Council, effective October 20, 1960.
Highway 612 was already paved at the time of the route's designation in 1960. No changes were made to the highway until the early 1970s, when jurisdiction over the portion of Highway 612 lying to the south of the Muskoka-Parry Sound District Boundary was transferred from the province to the District Municipality of Muskoka. Provincial ownership of the section of Highway 612 within Muskoka District ceased on April 30, 1972. This former section of Highway 612 is now known as Muskoka District Road 11. The 4.2 km section of Highway 612 lying within the District of Parry Sound is still a provincial highway today. Another, unrelated Highway 612 existed in the Elliot Lake area in the 1950s.