Highway 127 was designated in late 1955, generally following the same route as today, with the exception of the northern terminus.

During the early 1960s, a new road was constructed east of Whitney, bypassing the old highway for several kilometres.

It passes through large swaths of undeveloped forest on its 39 km (24 mi) journey, and is rather remote; aside from the towns at the northern and southern terminuses, the only named community on Highway 127 is Lake St.

[3] Like most routes which pass through the Canadian Shield, Highway 127 travels through rock cuts and muskeg-ridden terrain in the midst of dense coniferous forests.

[3] The following table lists the major junctions along Highway 127, as noted by the Ministry of Transportation of Ontario.