U.S. Route 240

U.S. Route 240 marker
U.S. Route 240
Washington National Pike
Wisconsin Avenue
Map
US 240 highlighted in red, US 240 Alt. in blue, and US 240 Truck in pink
Route information
Auxiliary route of US 40
Existed1926–1972
Major junctions
South end US 50 in Washington, D.C.
Major intersections I-270 / MD 355 near Bethesda, MD
I-70 in Frederick, MD
North end US 40 in Frederick, MD
Location
CountryUnited States
StatesDistrict of Columbia, Maryland
CountiesDC: Washington
MD: Montgomery, Frederick
Highway system
MD 239MD MD 242
US 211DC I-270

U.S. Route 240 is a defunct designation for a short, but once very important, segment of highway between Frederick, Maryland, and Washington, D.C. It is now commonly known as Wisconsin Avenue, Maryland Route 355 (MD 355), and Interstate 270 (I-270).