Maryland Route 648

Maryland Route 648 (MD 648) is a collection of state highways in the U.S. state of Maryland. These nine highways are current or former sections of the Baltimore–Annapolis Boulevard between Annapolis and Baltimore via Glen Burnie. There are five signed mainline segments of MD 648 through Arnold, Severna Park, Pasadena, Glen Burnie, Ferndale, and Pumphrey in northern Anne Arundel County; Baltimore Highlands in southern Baltimore County; and the independent city of Baltimore. MD 648 mainly serves local traffic along its meandering route, with long-distance traffic intended to use the parallel and straighter MD 2 south of Glen Burnie and freeway-grade Interstate 97 (I-97), I-695, and MD 295 between Glen Burnie and Baltimore.

The Baltimore–Annapolis Boulevard was constructed in the early to mid-1910s as the primary highway between Baltimore and Annapolis. The highway was specifically authorized by the Maryland General Assembly, which insisted the Maryland State Roads Commission complete the highway along its originally planned route instead of using what is now MD 2 north of Glen Burnie. The boulevard was designated parts of MD 2 and MD 3 in 1927; the latter number was replaced with U.S. Route 301 (US 301) in 1939. MD 648 was assigned to the Baltimore–Annapolis Boulevard south of Glen Burnie in the late 1930s after it was functionally replaced by MD 2's present course. In the late 1950s, after US 301 was moved to freeways from south of Glen Burnie to Baltimore, MD 648 was extended north from Glen Burnie into Baltimore. MD 648 has had few major changes since then, the most significant being relocations between Pasadena and Glen Burnie in the 1970s.