 By recapturing Detroit, the Americans had cut the principal route by which the British at Fort Mackinac and other posts in the North West were supplied.During the winter, the British opened an alternate route overland from York on Lake Ontario via Yonge Street to Holland Landing and the Holland River.From here, the route entered Lake Simcoe and led to the head of Kempenfeldt Bay (Barrie) where Nine Mile Portage led to Willow Creek, the Nottawasaga River and Lake Huron.