High Quality Content by WIKIPEDIA articles! The following is a list of U.S. Highways in Maryland. There are currently 14 U.S. Highways that exist entirely or partially in the U.S. state of Maryland. Seven of these are primary U.S. Highways while seven are auxiliary U.S. Highways that may or may not be related to one of the primary U.S. Highways. The longest primary U.S. Highway in Maryland is U.S. Route 40 (commonly abbreviated US 40) at 221.31 mi (356.16 km). The shortest primary U.S. Highway in Maryland is US 11 at 12.83 mi (20.65 km). The longest auxiliary U.S. Highway in Maryland is US 301 at 123.30 mi (198.43 km). The shortest auxiliary U.S. Highway in Maryland is US 522 at 2.37 mi (3.81 km). All U.S. Highways are maintained by the Maryland State Highway Administration except for the portions that run through Baltimore, Hagerstown, and Cumberland. Maryland has six former U.S. Highways; those six are shaded in dark gray in the list.