U.S. Route 20 in Idaho

U.S. Highway 20
U.S. Highway 20
Idaho Medal of Honor Highway
	US 20 highlighted in red
Route information
	Maintained by ITD
Length	406.30 mi (653.88 km)
Existed	1940–present
Major junctions
West end	US 20 / US 26 at the Oregon state line
	US 95 in Parma; I-84 / US 30 in Caldwell; I-84 / US 30 in Garden City; I-84 / US 26 / US 30 in Mountain Home; US 26 in Carey; US 26 / US 93 in Atomic City; I-15 in Idaho Falls;
East end	US 20 at the Montana state line
Location
Country	United States
State	Idaho
Counties	Payette, Canyon, Ada, Elmore, Camas, Blaine, Butte, Bingham, Bonneville, Jefferson, Madison, Fremont
Highway system
	United States Numbered Highway System; List; Special; Divided; Idaho State Highway System; Interstate; US; State;

U.S. Highway 20 (US 20) is the portion of an east–west United States Numbered Highway in the state of Idaho. It begins northwest of Parma at the Oregon state line and enters Montana 9.6 miles (15.4 km) away from the Yellowstone National Park west entrance.

Since 2019, US 20 has been designated as the Idaho Medal of Honor Highway.