History of Secondary Highway 600:
Secondary Highway 600 is a local highway in the District of Rainy River that provides access to a sizeable rural area and a handful of small communities lying to the north of Rainy River and Emo. Highway 600 was first depicted on a Preliminary Route Plan prepared by the Department of Highways of Ontario (DHO) in April 1956, and was designated by an Order-in-Council dated May 9, 1956. As originally assumed, Highway 600 extended for approximately 35 miles (56 km) from the Highway 615 Junction at Black Hawk to the Highway 623 Junction at Harris Hill. The highway was extended south to Rainy River during 1960, when the existing route of Highway 623 between Rainy River and Harris Hill was renumbered as Highway 600. A portion of the existing route of Highway 615 was also renumbered as Highway 600 between Black Hawk and the Highway 71 Junction north of Emo in 1960. The north and east extensions of Highway 600 brought the total length of the highway up to approximately 54 miles (87 km). Highway 600 was originally gravel-surfaced for its entire length. The highway was paved with a primed bituminous surface from Rainy River northerly to Hamilton Hill in 1963. During the 1970s, Highway 600 was paved between Hamilton Hill and the Highway 619 Junction, along with a section of Highway 600 from Black Hawk to the Highway 71 Junction. The balance of the highway from Black Hawk to the Highway 619 Junction is still gravel-surfaced today.
Apart from some small realignments in a few locations, very few changes occurred to the route of Highway 600 until recent decades. Jurisdiction over a short section of Highway 600 in Rainy River was transferred from the Ministry of Transportation of Ontario (MTO) to the Town of Rainy River, effective January 1, 1998. This 0.5 km section of Highway 600 extended north from the Highway 11 Junction near the International Bridge entrance to the north limits of the Town of Rainy River. However, this section of Highway 600 is still signed as such in order to preserve route continuity. Recent gold exploration at the Rainy River Mine north of Black Hawk has necessitated the relocation of a section of Highway 600 onto a new, improved alignment between Black Hawk and Dearlock. Unless posted otherwise, the speed limit on Highway 600 is 80 km/h (50 mph). There are no services available on this highway, apart from Rainy River at the highway's southern terminus.