Interstate 270

Interstate 270 travels 32.60 miles overall as a busy commuter route from I-495 northwest to I-70 and U.S. 40 at Frederick. The freeway sees a local/express roadway configuration from Exit 11 south to the split with I-270 Spur.
Interstate 270 Maryland Guides
Oldest portions of Interstate 270 date back to the 1950s-expressway of U.S. 240 through Frederick County. The route became a part of Interstate 70S in 1956. U.S. 240 shifted from its surface route, which was redesignated MD 355, to a freeway southward from Frederick to the Capital Beltway near Chevy Chase. The US route overlapped with I-70S to its decommissioning in 1972.1
Interstate 270 initially consisted of just the freeway spur to I-495 west from I-70S south in Montgomery County. Interstate 70S was renumbered as I-270 in 1973 when AASHTO mandated that all suffixed routes be dropped from the Interstate system. This left the original I-270 as I-270 Spur, a designation that remains in place today.1
Plans for Interstate 70S envisioned a continuation of the route southward into the District of Columbia. Ultimately dropped, as were many other Washington urban freeways due to community opposition, I-270 ends at a wye interchange with the Capital Beltway opposite the exit with MD 355 (former U.S. 240 leading south into D.C.)

Montrose Road meets Interstate 270 at a cloverleaf interchange by the Park Potomac master planned community. Initially the interchange was without the loop ramp onto Montrose Road west from I-270 north and the direct ramp from Montrose Road east onto I-270 south.
08/04/13
A loop ramp departs Montrose Road west to join the local lanes of Interstate 270 south ahead of the split with I-270 Spur. A second loop ramp follows from Montrose Road for Park Potomac Avenue.
08/04/13
MD 85 (Buckeystown Pike) north at the parclo interchange with Interstate 270 (Exit 31). The arterial meets the freeway adjacent to Francis Scott Key Mall, south of Frederick.
08/04/13
Interstate 270 north ends one mile beyond MD 85 at I-70/U.S. 40. U.S. 40 overtakes the freeway northward to U.S. 15 through Frederick while I-70 runs across southern reaches of the city between Hagerstown and Baltimore.
08/04/13
The entrance ramp to I-270 for U.S. 15 north and I-70/U.S. 40 departs MD 85 (Buckeystown Pike) north. MD 85 continues another mile to MD 355 (Urbana Pike / historic U.S. 240) ahead of I-70 (Exit 54).
08/04/13
Spectrum Drive encircles Francis Scott Key Mall east from MD 85 (Buckeystown Pike) within vicinity of I-270.
08/04/13
The final mile of I-270 leads north from MD 85 (Buckeystown Pike) to Interstate 70, U.S. 15 and U.S. 40.
08/04/13
Passing under the Interstate 270 mainline, MD 85 nears the southbound on-ramp to Germantown, Gaithersburg, Rockville and Washington, DC.
08/04/13
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- AARoads: 08/04/13
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Page Updated Saturday June 07, 2014.