A total of at least three special routes of U.S. Route 9 (US 9) exist and at least seven have been decommissioned.

U.S. Route 9 (US 9) is a United States Numbered Highway in the Northeastern U.S., running from Laurel, Delaware, north to Champlain, New York. In Delaware, the route runs a southwest–northeast path through Sussex County. Even though US 9 is signed north–south for the remainder of its route, the segment in Delaware is signed east–west. The highway runs from its western terminus at US 13 in Laurel northeast to the Cape May–Lewes Ferry terminal in Lewes, where the ferry carries the route across the Delaware Bay to North Cape May, New Jersey. US 9 passes through rural areas and serves the communities of Laurel, Georgetown, and Lewes. US 9 intersects Delaware Route 20 (DE 20) in Hardscrabble, US 113 and DE 18/DE 404 in Georgetown, DE 30 in Gravel Hill, DE 5 in Harbeson, and DE 1 at the Five Points intersection in Nassau. US 9 runs concurrent with DE 404 between Georgetown and Five Points and with DE 1 between Five Points and Carpenters Corner.