

This section crosses the Susquehanna River at the north end of the Chesapeake Bay on the Thomas J. 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 (named for American Revolutionary War (1775–1783) foreign military volunteer of Polish cavalry officer Casimir Pulaski, 1745–1779).

West of Baltimore, in the Piedmont andĪppalachian 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. 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 (MD 144). With a total length of 221 miles (356 km), it is the longest numbered highway in Maryland. state of Maryland runs from Garrett County in Western Maryland to Cecil County in the state's northeastern corner. Garrett, Allegany, Washington, Frederick, Carroll, Howard, Baltimore, City of Baltimore, Harford, Cecil US 40 at Pennsylvania border near Keysers Ridge Maintained by MDSHA, Baltimore DOT, and MDTA
