is a long highway that runs Northwest to Southeast in
Maryland . The highway begins in
Suitland, Maryland at the state line with
Washington, DC and runs to
Leonardtown, Maryland . The roadway itself is an extension of
Pennsylvania Avenue .
According to Mike Pruett at
MDRoads.com , Route 4 is one of the original state highways, originally being designated as Marlboro Pike through
Upper Marlboro .
Route 4 also services
District Heights ,
Andrews Air Force Base , Upper Marlboro,
Waysons Corner ,
Dunkirk ,
Huntingtown ,
Prince Frederick ,
Lusby ,
Calvert Cliffs State Park , the
Calvert Cliffs Nuclear Power Plant , and
California .
Route 4 meets with
Maryland State Highway 2 in
Calvert County . The two are multiplexed as "Route 2/4" for over 25 miles before Route 2 leaves the highway to enter
Solomons Island . Route 4 continues toward Leonardtown and
St. Mary's County across the
Governor Thomas Johnson Bridge across the
Patuxent River .
Route 4 ends in Leonardtown at an intersection with
Maryland State Highway 5 .
