Delaware Route 1

Delaware Route 1
DE 1 highlighted in red; DE 1A highlighted in yellow; DE 1B highlighted in teal; DE 1D highlighted in blue; DE 1 Bus. highlighted in green
Route information
Maintained by DelDOT and USACE
Length	102.63 mi[1] (165.17 km)
Existed	1974[2]–present
History	Completed in 2003[3][4]
Tourist routes	Delaware Bayshore Byway Washington–Rochambeau Revolutionary Route
Major junctions
South end	MD 528 in Fenwick Island
Major intersections	US 9 / DE 404 in Nassau US 113 in Milford DE 9 near Dover AFB US 13 in Dover US 13 / DE 896 in Boyds Corner US 301 Toll in Biddles Corner US 13 in Tybouts Corner US 40 in Bear DE 273 near Christiana DE 7 in Christiana
North end	I-95 / DE 7 in Christiana
Location
Country	United States
State	Delaware
Counties	Sussex, Kent, New Castle
Highway system
Delaware State Route System List Byways
← DE 896 → DE 1A

Delaware Route 1 (DE 1) is the longest numbered state highway in the U.S. state of Delaware. The route runs 102.63 mi (165.17 km) from the Maryland state line in Fenwick Island, Sussex County, where the road continues south into that state as Maryland Route 528 (MD 528), north to an interchange with Interstate 95 (I-95) in Christiana, New Castle County, where the roadway continues north as part of DE 7. Between Fenwick Island and Dover Air Force Base in Dover, Kent County, DE 1 is a multilane divided highway with at-grade intersections and occasional interchanges. The route heads north through the Delaware Beaches resort area along the Atlantic Ocean before it runs northwest through rural areas, turning north at Milford to continue to Dover. Upon reaching Dover, DE 1 becomes the Korean War Veterans Memorial Highway, a freeway that is partially tolled. Between Dover and Tybouts Corner, DE 1 parallels U.S. Route 13 (US 13), crossing over and featuring interchanges with it multiple times. Past Tybouts Corner, the freeway heads north parallel to DE 7 to the northern terminus of DE 1 in Christiana. DE 1 serves as the main north-south state highway in Delaware, connecting the Delaware Beaches with the Dover and Wilmington areas.

DE 1 was first designated in the 1970s from Fenwick Island north to US 113 in Milford, replacing a portion of DE 14 south of Milford and following the newly-constructed Milford Bypass. DE 14 between Fenwick Island and Milford had been built as a state highway in the 1920s and 1930s and was widened into a divided highway between the 1950s and 1970s. In the 1980s, a controlled-access "Relief Route" of US 13 was proposed between Dover and the Wilmington area in order to relieve that route of beach traffic. This proposed highway was incorporated into DE 1 in 1988, with the route extended north concurrent with US 113 between Milford and Dover to connect to the Relief Route. The DE 1 freeway between Dover Air Force Base and Christiana opened in multiple stages between 1991 and 2003, and at a cost of $900 million was the largest public works project in Delaware history. The concurrent US 113 designation between Milford and Dover Air Force Base was removed in 2004. Upgrades continue to be made to DE 1 such as the construction and improvement of interchanges as well as widening portions of the road.