Maryland Route 2 is the longest state highway in the U.S. state of Maryland. The 79.24-mile (127.52 km) route runs from Solomons Island in Calvert County north to an intersection with U.S. Route 1 /US 40 Truck in Baltimore. The route runs concurrent with MD 4 through much of Calvert County along a four-lane divided highway known as Solomons Island Road, passing through rural areas as well as the communities of Lusby, Port Republic, Prince Frederick, and Huntingtown. In Sunderland, MD 2 splits from MD 4 and continues north as two-lane undivided Solomons Island Road into Anne Arundel County, still passing through rural areas. Upon reaching Annapolis, the route runs concurrent with US 50/US 301 to the north of the city. Between Annapolis and Baltimore, MD 2 runs along the Governor Ritchie Highway, a multilane divided highway that heads through suburban areas, passing through Arnold, Severna Park, Pasadena, Glen Burnie, and Brooklyn Park. In Baltimore, the route heads north on city streets and passes through the downtown area of the city.

Calvert County is a county located in the U.S. state of Maryland. As of the 2020 census, the population was 92,783. Its county seat is Prince Frederick. The county's name is derived from the family name of the Barons of Baltimore, the proprietors of the English Colony of Maryland. Calvert County is included in the Washington–Arlington–Alexandria, DC–VA–MD–WV Metropolitan Statistical Area. It occupies the Calvert Peninsula, which is bordered on the east by Chesapeake Bay and on the west by the Patuxent River. Calvert County is part of the Southern Maryland region. The county has one of the highest median household incomes in the United States. It is one of the older counties in Maryland, after St. Mary's, Kent County and Anne Arundel counties.