In the early 19th century, Lake Placid and Keene were connected by the North West Bay Road, an east–west highway linking Hopkinton to Westport. The highway was initially a crude, impassable road; however, it was significantly improved by the state of New York in the mid-1810s. A highway linking Keene to Underwood was constructed by 1846; at Underwood, the road connected to a stagecoach road that went from Albany to the Canada–US border. The latter road became the basis for most of modern US 9.