Tertiary Highway 811, commonly referred to as Highway 811, is the longest of Ontario's tertiary highways, and the highest posted route number in the province. The route encounters no named roads along its route, aside from its eastern terminus at Secondary Highway 527. It extends 59 kilometres (37 mi) westward into the wilderness, ending at a bridge over the Weaver River. The route was designated in 1976 with the intention of extending it further west, but this extension has yet to be constructed.