Maryland Route 4 is a state highway in the U.S. state of Maryland. The highway runs 64.85 miles (104.37 km) from MD 5 in Leonardtown north to Southern Avenue in Suitland at the District of Columbia boundary, beyond which the highway continues into Washington as Pennsylvania Avenue. MD 4 is a four- to six-lane highway that connects Washington and communities around Interstate 95 (I-95)/I-495 with southern Prince George's County with southwestern Anne Arundel County. The highway is the primary highway for the length of Calvert County, during most of which the route runs concurrently with MD 2. MD 4 also connects Calvert and St. Mary's counties via the Governor Thomas Johnson Bridge across the Patuxent River. The highway connects the Southern Maryland county seats of Leonardtown, Prince Frederick, and Upper Marlboro.

Maryland Route 5 is a 74.34-mile (119.64 km) long state highway that runs north–south in the U.S. state of Maryland. The highway runs from Point Lookout in St. Mary's County north to the Washington, D.C. border in Suitland, Prince George's County. MD 5 begins as two-lane undivided Point Lookout Road which runs from Point Lookout to an intersection with MD 235 in the northern part of St. Mary's County. Point Lookout Road passes through rural areas as well as the county seat of Leonardtown. After the MD 235 intersection, the route becomes four-lane divided Three Notch Road and continues into Charles County, where it becomes Leonardtown Road. Here, the route bypasses Hughesville and continues north toward the Waldorf area, which it bypasses to the east on Mattawoman Beantown Road. The route merges onto U.S. Route 301 and enters Prince George's County, splitting from US 301 at an interchange in Brandywine. From here, MD 5 continues north on Branch Avenue, running through suburban areas, before becoming a freeway as it passes Andrews Air Force Base and has an interchange with Interstate 95 (I-95)/I-495. Past the Capital Beltway, the route runs through suburban areas of Hillcrest Heights and Suitland before reaching the Washington, D.C. border, where Branch Avenue SE continues, crossing Pennsylvania Avenue SE and eventually terminating at Randle Circle.