Secondary Highway 531, commonly referred to as Highway 531, is a provincially maintained secondary highway in the Canadian province of Ontario. It connects Highway 17 east of North Bay with the community of Bonfield. The 3.5-kilometre (2.2 mi) route was established in 1956, and has remained the same since then. It passes through a forested area and has several private residences located along its length. Aside from Maple Road, its southern terminus, and Highway 17, its northern terminus, Highway 531 encounters no roads along its length.
^ ab"Ontario Secondary Roads Now Designated 500, 600". 112 (33,119). The Globe and Mail. February 4, 1956. p. 4. Two new Ontario road numbers appear on the province's 1956 official road map which will be ready for distribution next week. The new numbers are the 500 and 600 series and designate hundreds of miles of secondary roads which are wholly maintained by the Highways Department. More than 100 secondary roads will have their own numbers and signs this year. All of these secondary roads were taken into the province's main highways system because they form important connecting links with the King's Highways