U.S. Route 40 in Maryland in the context of Maryland Route 355

Maryland Route 122 (MD 122) is a state highway in the U.S. state of Maryland. Known as Security Boulevard, the state highway runs 2.96 miles (4.76 km) from Rolling Road east to the Baltimore city line within the western Baltimore County suburb of Woodlawn. MD 122 serves the headquarters of the Social Security Administration and connects the agency with MD 570, I-695, and U.S. Route 40 (US 40). Security Boulevard was constructed in 1960 concurrent with the completion of the Social Security Administration's new headquarters. The highway was transferred from county to state maintenance around 1991.

Western Maryland, also known as the Maryland panhandle or Mountain Maryland, is the portion of the U.S. state of Maryland that typically consists of Washington, Allegany, and Garrett counties. The region is bounded by the Mason-Dixon line (Pennsylvania) to the north, the Potomac River and West Virginia to the south, and Preston County, West Virginia to the west. At one point, at the town of Hancock, the northern and southern boundaries are separated by just 1.8 miles (2.9 km), the narrowest stretch in the state.

Western Maryland is more rural than the Washington-Baltimore area, where most of the state's population lives, and is noted for its mountainous terrain. The area is in the central Appalachians. Washington, Allegany, and Garrett counties are part of the Appalachian Regional Commission. The most populous community in Western Maryland is Hagerstown, located in Washington County, the most populous county in the region. Major highways in Western Maryland include Interstate Highways I-70, I-81 and I-68; U.S. Highways U.S. 11, U.S. 40, U.S. 40 ALT, U.S. 219 and U.S. 50; and several state highways.

The Baltimore–Washington Parkway (also referred to as the B–W Parkway) is a controlled-access parkway in the U.S. state of Maryland, running southwest from Baltimore to Washington, D.C. The road begins at an interchange with U.S. Route 50 (US 50) near Cheverly in Prince George's County at the Washington, D.C., border, and continues northeast as a parkway maintained by the National Park Service (NPS) to MD 175 near Fort Meade, serving many federal institutions. This portion of the parkway is dedicated to Gladys Noon Spellman, a representative of Maryland's 5th congressional district, and has the unsigned Maryland Route 295 (MD 295) designation. Commercial vehicles, including trucks, are prohibited within this stretch. This section is administered by the NPS's Greenbelt Park unit. After leaving park service boundaries the highway is maintained by the state and signed with the MD 295 designation. This section of the parkway passes near Baltimore–Washington International Thurgood Marshall Airport.

Upon entering Baltimore, the Baltimore Department of Transportation takes over maintenance of the road and it continues north to an interchange with Interstate 95 (I-95). Here, the Baltimore–Washington Parkway ends and MD 295 continues north unsigned on Russell Street, which carries the route north into downtown Baltimore. In downtown Baltimore, MD 295 follows Paca Street northbound and Greene Street southbound before ending at US 40.