Maryland Route 408 (MD 408) is a state highway in the U.S. state of Maryland. Known as Mount Zion-Marlboro Road, the highway runs from MD 4 at Waysons Corner east to MD 2 and MD 422 in Lothian. MD 408 is the old alignment of MD 4 in southern Anne Arundel County. The highway was constructed in the late 1910s and became the easternmost part of MD 4 in 1927. The highway received its present designation in the mid-1960s when MD 4 was rerouted south into Calvert County. MD 408's western end was relocated when MD 4 was upgraded to a freeway through Waysons Corner in the early 1990s. MD 408 was also applied to the old sections of MD 4 between Andrews Air Force Base and Upper Marlboro in Prince George's County. The number was assigned after the MD 4 freeway was completed in the mid-1960s. The Prince George's County portions of MD 408 were transferred to county maintenance in the late 1970s except the section through Upper Marlboro, which became MD 725. Route description MD 408 begins at a three-quarter diamond interchange with MD 4 (Stephanie Roper Highway) just west of Waysons Corner. The roadway continues south from the interchange as MD 980A, a service road that curves east and parallels southbound MD 4 toward Bristol. The missing ramp in the diamond interchange, the movement from northbound MD 4 to MD 408, is made via MD 794 (Southern Maryland Boulevard) just to the southeast. MD 408 continues east as a two-lane undivided road through a mix of commercial development, residences, and farmland. The highway veers northeast beyond its intersection with MD 259 (Greenock Road) and passes the historic home Quarter Place. MD 408 reaches its eastern terminus in Lothian at a four-way roundabout from which MD 2 (Solomons Island Road) heads northeast toward Annapolis and southeast in the direction of Prince Frederick, and MD 422 heads northwest along Bayard Road. History MD 408 is the old alignment of MD 4 from Waysons Corner to Lothian. With the road from Washington to Waysons Corner, the highway was included in the original state road system designed by the Maryland State Roads Commission in 1909 as part of the main road between Washington and Annapolis. The highway was constructed as a gravel road between 1916 and 1919 and designated the eastern end of MD 4 in 1927. MD 4 was paved