U.S. Route 240

U.S. Route 240
U.S. Route 240
Washington National Pike; Wisconsin Avenue
	US 240 highlighted in red, US 240 Alt. in blue, and US 240 Truck in pink
Route information
	Auxiliary route of US 40
Existed	1926–1972
Major junctions
South end	US 50 in Washington, D.C.
	I-270 / MD 355 near Bethesda, MD; I-70 in Frederick, MD
North end	US 40 in Frederick, MD
Location
Country	United States
States	District of Columbia, Maryland
Counties	DC: Washington; MD: Montgomery, Frederick
Highway system
	United States Numbered Highway System; List; Special; Divided;

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).