Maryland Route 85 (MD 85) is a state highway in the U.S. state of Maryland. Known as Buckeystown Pike, the state highway runs from MD 28 in Tuscarora north to the Frederick city limit north of Interstate 70 (I-70), where the highway continues north as East Street. MD 85 connects Tuscarora and Buckeystown in southern Frederick County with the county seat of Frederick. The state highway also links the suburban area between Buckeystown and Frederick with I-70 and I-270. MD 85 is the old alignment of U.S. Route 15 (US 15), which was originally constructed between Tuscarora and Frederick in the late 1910s and early 1920s. MD 85 was assigned to the highway in 1970 when US 15 was moved to a new highway heading north from its Potomac River crossing at Point of Rocks. The state highway was extended north to the city of Frederick as part of a project to overhaul MD 355's interchange with I-70 in the first decade of the 21st century.