Maryland Route 337, Allentown Road, is a short road in Prince George's county, Maryland. It begins at its intersection with Maryland Route 5 and ends at MD Route 4, going east through the communities of Camp Springs and Forestville. The main entrance to Joint Base Andrews is on Allentown Road.
Maryland Route 337 begins along Allentown Road at an single-point urban interchange with MD 5 (Branch Avenue). It travels east from Camp Springs along a four-lane road, featuring a shared left-turn lane in the center. The route then enters Morningside, where it serves a retail area. As the route begins to approach the Capital Beltway, the development eases away and the route begins to feature a grassy median.
After the route intersects Forestville Road, which provides some access to the Capital Beltway, the route begins to circle around the northeastern edge of Joint Base Andrews, paralleling its Perimeter Road on the east side. Along this path, maintenance switches over to the government. The road's four lanes narrow to two, and the westbound lane also ends; the road becomes an eastbound only ramp leading into eastbound Suitland Parkway. Traffic travelling west along Suitland Parkway can use Forestville Road, which also intersects the road, and is marked on some maps as MD 337. Government control of the road continues onto the four-lane divided Suitland Parkway until it meets a trumpet interchange leading directly into the base. Here, maintenance returns to the state for the remainder of its journey, which is only a short stretch to MD 4 (Pennsylvania Avenue).
The entire route is in Prince George's County.