What is the longest USA highway?
U.S. Route 20
US 20 continues from Sudbury through Wayland, Weston, Waltham, Watertown and then into Boston through Allston and Fenway–Kenmore. U.S. Route 20's official eastern terminus is in Kenmore Square at the intersection of Commonwealth Avenue, Beacon Street, and Brookline Avenue, where the alignment becomes Massachusetts Route 2. Route 2 continues for a short distance where it terminates at U.S. Route 3.