"The Old Mail Road"
For some years prior to the by-law which established it as a public road in 1846, this route had been travelled by settlers destined for the newly-opened townships of Osprey, Collingwood, Euphrasia and St. Vincent. From its junction near Duntroon with an extension of the Sunnidale Road, it ran some 34 km northwesterly to Griersville. Though it was entitled to maintenance by statute labour, the road was chronically in poor repair. Nevertheless, it remained an official road until its usefulness ended when the Ontario, Simcoe and Huron Railway reached Collingwood in 1855. Save for this 8 km section still in use between Griersville and Heathcote, little evidence remains of the pioneer road.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.