with Old Crain Highway allowing access to and from the west and a modified diamond interchange with Ritchie Marlboro Road, the portion of which between the highway and parallel Old Marlboro Pike to the north is another segment of MD 980. MD 4 has a partial cloverleaf interchange with the eastern end of MD 223 (Woodyard Road) in Melwood before the freeway ends and the highway expands to six lanes at Dower House Road. The highway heads northwest along the northeastern edge of the Andrews Air Force Base to an intersection with Suitland Parkway, which provides access to the military installation and leads west to MD 337 (Allentown Road). North of the parkway, MD 4 drops to four lanes at its cloverleaf interchange with I-95/I-495 (Capital Beltway) in Forestville. The highway intersects Forestville Road, which leads to the parallel Marlboro Pike. MD 4 intersects MD 458 (Silver Hill Road) south of District Heights, then parallels Oxon Run between Coral Hills and Cedar Hill Cemetery before reaching the District of Columbia boundary on the northern edge of Suitland at Southern Avenue. Pennsylvania Avenue continues northwest straight toward downtown Washington. History MD 4 in Prince George's County was originally the Washington and Marlborough Turnpike, which exited the District of Columbia on Bowen Road, headed east to Forestville, south to Meadows, then east through Upper Marlboro to Hills Bridge on the Patuxent River. An unnamed road continued east to Solomons Island Road in Lothian. When the Maryland State Roads Commission was established in 1908, this route became one of the original state roads. In 1910, the highway was paved from the D.C. border to what is today District Heights, as well as from Hills Bridge to Waysons Corner, where MD 4 meets MD 408 today. Marlboro Pike from the D.C. line to Hills Bridge and Mt. Zion Road between Hills Bridge and Lothian was fully paved by 1927, which was the same year MD 4 was assigned to the two named roads. Southern Maryland Boulevard was built between Waysons Corner and MD 2 in Sunderland in 1929 and 1930, and was designated MD 416 by 1933. Pennsylvania Avenue was extended east out of D.C. to Dower House Road as a controlled access four-lane divided highway in 1959 and 1960 and was designated MD 4. Marlboro Pike was assigned MD 4 Business, a designation that was gone by 1970. Also in 1960, the MD