AARoads:Maryland/National Highway System
The National Highway System is...
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For the purpose of this page, the National Highway System is divided into two classifications, primary and secondary. The primary system consists of the Interstate Highway System, Other NHS Routes, STRAHNET Connectors, and Non-Interstate STRAHNET Routes. This system is designated simply NHS System in the Highway Location Reference. The secondary system consists of Intermodal Connectors and MAP-21 Principal Arterials; the latter is a system that was added to the system in September 2012. Primary system segments are bold in the lists below. Routes that are included in the National Highway System by virtue of running concurrently with another highway are italic.
Interstate Highways
All portions of the Interstate Highway System are part of the National Highway System by definition.
U.S. Highways
US 1 from Washington to I-695 in Overlea; I-695 to the Pennsylvania state line
US 11 from I-81 in Williamsport to the Pennsylvania state line
US 13 from the Virginia state line to the Delaware state line
US 15 from the Virginia state line to the Pennsylvania state line
US 29 from Washington to I-70 in Ellicott City; I-70 to MD 99
US 40 from the Pennsylvania state line to I-68 at Keyser's Ridge; west of Hagerstown to I-70 east of Hagerstown; I-70 Exit 48 west of Frederick to US 15 in Frederick; I-70 west of Ellicott City to I-695 in Catonsville; I-695 to I-95 in Baltimore; I-95 to east of Perryville; through North East; MD 279 to the Delaware state line