U.S. Route 5 (US 5) is a north–south United States Numbered Highway running through the New England states of Connecticut, Massachusetts, and Vermont. Significant cities along the route include New Haven, Connecticut; Hartford, Connecticut; and Springfield, Massachusetts. From Hartford northward to St. Johnsbury, Vermont, the road closely follows the route of the Connecticut River. The entire route of US 5 is closely paralleled by Interstate 91 (I-91). US 5 now serves as the local business route and alternate route for the Interstate Highway. The northern terminus of US 5 is in Derby Line, Vermont, at the Canada–US border, where it continues past the Derby Line–Stanstead Border Crossing into Quebec as Route 143, which was Route 5 until renumbered in the mid-1970s. Its southern terminus is in New Haven, Connecticut, at an intersection with I-91. From Wikipedia