The designation Sea to Sky Highway ends at Mount Currie , though Highway 99 continues on northwards over Cayoosh Pass to Lillooet. Locations beyond Mount Currie-Lillooet Lake along the route of the rail line and the frontier-era Douglas Road are not usually considered in the Corridor, but sometimes are even though they are not on the Sea to Sky Highway. This further subregion is defined by the lower valley of the Birkenhead River and the Birken Valley and Gates Valley towards Anderson Lake. Socially and economically this area is part of or adjunct to the Pemberton subregion, though not in the Pemberton Valley: