What is now US 9 in Delaware was originally built as a state highway during the 1920s and designated by 1936 as DE 28 between Laurel and Georgetown and a part of DE 18 between Georgetown and Lewes. US 9 was extended to Delaware from New Jersey by way of the Cape May–Lewes Ferry in 1974, replacing all of DE 28 and the portion of DE 18 between Georgetown and Five Points, with the route aligned to bypass Lewes. DE 404 was designated along the portion of US 9 between Georgetown and Five Points by 1987.