Charlestown is a town in Cecil County, Maryland, United States. The population was 1,183 at the 2010 census.

Maryland Route 7 (MD 7) is a collection of state highways in the U.S. state of Maryland. Known for much of their length as Philadelphia Road, there are five disjoint mainline sections of the highway totaling 40.23 miles (64.74 km) that parallel U.S. Route 40 (US 40) in Baltimore, Harford, and Cecil counties in northeastern Maryland. The longest section of MD 7 begins at US 40 just east of the city of Baltimore in Rosedale and extends through eastern Baltimore County and southern Harford County to US 40 in Aberdeen. The next segment of the state highway is a C-shaped route through Havre de Grace on the west bank of the Susquehanna River. The third mainline section of MD 7 begins in Perryville on the east bank of the Susquehanna River and ends at US 40 a short distance west of the start of the fourth section, which passes through Charlestown and North East before ending at US 40, just west of Elkton. The fifth segment of the highway begins at South Street and passes through the eastern part of Elkton before reconnecting with US 40 east of Elkton and west of the Delaware state line.