The segment of DE 1 between US 13 south of Odessa and US 13 in St. Georges opened in November 1999. DE 1 was subsequently rerouted off US 13 between those two points. The construction of the final segment of DE 1 between Smyrna and Odessa resulted in a portion of US 13 south of Odessa being shifted further east as DE 1 would be built on top of the road. A service road would serve properties on the southbound side of US 13. In October 2001, northbound US 13 was realigned to the new alignment south of Odessa in order to build DE 1 in that area. In May 2002, US 13 was shifted to a new southbound alignment south of Odessa, with the former portion of the route in that area becoming a service road known as Harris Road. The final section of DE 1 between Smyrna and Odessa opened on May 21, 2003. As a result, DE 1 was moved off US 13 between Smyrna and Odessa.