History of Secondary Highway 533:
Secondary Highway 533 is a local highway in the District of Nipissing that extends from Highway 63 south of Eldee to Highway 17 in Mattawa. The Harrington Creek Road northwest of Mattawa was designated as Highway 533 by an Order-in-Council dated May 9, 1956, and was first depicted on a Preliminary Route Plan prepared by the Department of Highways of Ontario (DHO) in September, 1956. Highway 533 began at the Highway 17 Junction in Downtown Mattawa and extended for approximately 17 miles (27 km) to Crooked Lake. The first 3 miles of Highway 533 were already paved at the time of designation in 1956, but the balance of the highway was gravel-surfaced. Work had been underway since the Winter of 1954-1955 to extend the Harrington Creek Road north from Crooked Lake to connect with Highway 63. A road was finally punched through and opened to traffic in 1957. The Harrington Creek Road from Crooked Lake to Highway 63 was officially designated as an extension of Highway 533 by an Order-in-Council, effective October 2, 1958. The new extension added approximately 16 miles (26 km) to the length of Highway 533. Paving work resumed on Highway 533 immediately north of the Highway 656 Junction in 1962. A primed bituminous surface was constructed from Highway 63 southerly for 6 miles in 1967. Highway 533 was first shown with a completely paved surface on the 1973 Edition of the Ontario Official Road Map.
The section of Highway 533 which passed through the incorporated limits of Mattawa was not initially assumed as a Secondary Highway by the DHO. This section of the road remained under municipal jurisdiction for several years, but was ultimately assumed as part of the highway in preparation for a major reconstruction of the town's main street. On June 9, 1969, an Assumption Plan was prepared which showed the proposed assumption of Highway 533 from the north town limits at Grahame Street to the end of Highway 533 at McConnell Street (Highway 17). The DHO assumed jurisdiction over the section of Highway 533 through Mattawa once the survey plan was registered on July 16, 1969. Jurisdiction over the highway was ultimately transferred back to the Town of Mattawa in 1971, following the highway's reconstruction. The section of Highway 533 lying within the town limits was transferred from the province back to the Town of Mattawa, effective July 30, 1971. The highway through Mattawa was designated as a Municipal Connecting Link, which came into effect in July, 1971.
Apart from a few minor realignments, the route of Highway 533 has not changed significantly since the 1950s. Unless posted otherwise, the speed limit on Highway 533 is 80 km/h (50 mph). There are no services located along Highway 533, apart from those offered in Mattawa at the highway's southern terminus.