History of Secondary Highway 546:
Secondary Highway 546 is a local highway in the District of Algoma that provides access to Highway 554 and a number of lakes lying northeast of Iron Bridge. Highway 546 was first designated by an Order-in-Council dated May 9, 1956. The route was first depicted on a Preliminary Route Plan prepared by the Department of Highways of Ontario (DHO) in June, 1956. The new highway was originally 46 miles (74 km) in length. Highway 546 began at the Highway 17 Junction in Iron Bridge and headed northeasterly where it ended at Mount Lake. The highway was gravel-surfaced at the time of designation in 1956, but the highway was paved from Iron Bridge to Mount Lake in sections between 1976 and 1980. Unless posted otherwise, the speed limit on Highway 546 is 80 km/h (50 mph). There are no services available along Highway 546 north of Iron Bridge. The route of Highway 546, in conjunction with Highway 639 and Highway 108, forms a scenic loop through the Algoma Highlands via Elliot Lake.