 In 1974 , DE 1 was signed concurrent with DE 14 east of Milford and on the Milford Bypass . Work began in 1975 to widen the portion of DE 14 bypassing Rehoboth Beach , which included a new bridge over the Lewes and Rehoboth Canal . In 1977 , DE 14 was truncated to Milford , with DE 1 replacing the route between Fenwick Island and the south end of the Milford Bypass . As a result of this , DE 14A was renumbered to DE 1A . A new high @-@ level bridge carrying DE 1 over the Lewes and Rehoboth Canal opened in 1978 . By 1981 , DE 1 was widened to a divided highway between Dewey Beach and southwest of Rehoboth Beach except for the crossing of the canal . In 1985 , the crossing over the Lewes and Rehoboth Canal was dualized with a high @-@ level bridge constructed for northbound traffic . DE 1 was designated along US 113 between Milford and Dover in 1988 . In 2004 , the concurrent US 113 designation along DE 1 between Milford and Dover Air Force Base was removed . On September 11 , 2006 , work began on a $ 9 @.@ 7 million project to widen DE 1 between DE 24 in Midway and US 9 in Five Points by adding a third southbound lane and a multi @-@ use lane in both directions . The project was completed on June 9 , 2008 . 
