Maryland Route 64 is a state highway in the U.S. state of Maryland. The state highway runs 13.33 miles (21.45 km) from U.S. Route 40 in Hagerstown east to the Pennsylvania state line near Ringgold, where the highway continues north as Pennsylvania Route 997. MD 64 is an L-shaped route in northeastern Washington County, connecting Hagerstown with Smithsburg, Cavetown, and Chewsville and Smithsburg with Ringgold and Waynesboro, Pennsylvania. The state highway is maintained by the Maryland State Highway Administration except for the municipally-maintained portion within the city limits of Hagerstown. MD 64 was once a turnpike between Hagerstown and Smithsburg. The state highway was constructed from Smithsburg to the Pennsylvania state line in the mid 1910s and from Hagerstown to Smithsburg in the early 1920s. MD 64 was reconstructed in its entirety in the 1950s, resulting in bypasses of all four communities east of Hagerstown the highway serves.

U.S. Route 40 in the U.S. state of Maryland runs from Garrett County in Western Maryland to Cecil County in the state's northeastern corner. With a total length of 221 miles (356 km), it is the longest numbered highway in Maryland. Almost half of the road overlaps or parallels with Interstate 68 (I-68) or I-70, while the old alignment is generally known as US 40 Alternate, US 40 Scenic, or Maryland Route 144. West of Baltimore, in the Piedmont and Appalachian Mountains / Blue Ridge region of the Western Maryland panhandle of the small state, the portions where it does not overlap an Interstate highway are mostly two-lane roads. The portion northeast of Baltimore going toward Wilmington in northern Delaware and Philadelphia in southeastern Pennsylvania is a four-lane divided highway, known as the Pulaski Highway. This section crosses the Susquehanna River at the north end of the Chesapeake Bay on the Thomas J. Hatem Memorial Bridge.