History of Secondary Highway 577:
Secondary Highway 577 is a local highway in the District of Cochrane that provides access between Highway 101 at Shillington to Highway 11 near Monteith. Up until the late 1990s, the route of Highway 577 extended even further north into Iroquois Falls. Highway 577 was first designated by an Order-in-Council dated May 9, 1956. Initially, the highway was 15.2 miles (24.5 km) in length. The route began west of Matheson at the Highway 101 Junction at Shillington and extended north to Iroquois Falls, via Monteith. As originally designated in 1956, Highway 577 ended at the Highway 67 Junction at the intersection of Main Street and Synagogue Street in Iroquois Falls. A short section of Highway 577 ran concurrently with Highway 11 (the Monteith Diversion) across the Driftwood River Bridge. Initially, the entire highway was gravel-surfaced, but the route was paved from Shillington to Highway 11 in 1966 and from Highway 11 to Iroquois Falls in 1975.
As originally assumed in the 1950s, the Department of Highways of Ontario (DHO) owned Highway 577 in its entirety. During the early 1970s, jurisdiction over a portion of Highway 577 in the Iroquois Falls area was transferred from the province to local municipalities. On April 1, 1970, the section of Highway 577 from the Meadow Creek Bridge to the Highway 67 Junction at Main Street and Synagogue Street was transferred to the Township of Calvert and the Town of Iroquois Falls. This 0.6 mile (1 km) section of Highway 577 was designated as a Municipal Connecting Link by an Order-in-Council, effective July 21, 1971. The Municipal Connecting Link through Iroquois Falls remained in existence up until the late 1990s, when it was revoked by a Minister's Order, effective November 9, 1998.
During the late 1990s, the province transferred a section of Highway 577 to the Town of Iroquois Falls. Jurisdiction over the 13 km section of Highway 577 from the Highway 11 Junction near Monteith to the Meadow Creek Bridge in Iroquois Falls was transferred to the municipality on March 31, 1997. The short overlapped section of Highway 577 between the north and south junctions of Highway 11 was also discontinued. Since 1997, Highway 577 has stood at 10.6 km in length. The route now only connects Highway 11 to Highway 101 at Shillington. Unless posted otherwise, the speed limit on Highway 577 is 80 km/h (50 mph). Trucks are prohibited on Former Highway 577 (Critchley Avenue and Monteith Road) between Monteith and Iroquois Falls. There are no services available on Highway 577.