U.S. Route 12 in Montana

U.S. Highway 12
U.S. Highway 12
Lewis and Clark Highway
	US 12 highlighted in red
Route information
	Maintained by MDT
Length	597.576 mi (961.705 km)
Existed	1926–present
Tourist; routes	Lewis and Clark Trail
Major junctions
West end	US 12 at the Idaho state line at Lolo Pass
	US 93 from Lolo to Missoula; I-90 from Missoula to Garrison; MT 200 from Missoula to West Riverside; I-15 in Helena; US 287 from Helena to Townsend; US 89 near White Sulphur Springs; US 191 in Harlowton; US 87 in Roundup; I-94 from Forsyth to Miles City;
East end	US 12 at the North Dakota state line east of Baker
Location
Country	United States
State	Montana
Counties	Missoula, Granite, Powell, Lewis and Clark, Jefferson, Broadwater, Meagher, Wheatland, Golden Valley, Musselshell, Rosebud, Custer, Fallon
Highway system
	United States Numbered Highway System; List; Special; Divided; Montana Highway System; Interstate; US; State; Secondary;

U.S. Highway 12 (US 12) is an east–west United States Numbered Highway in the state of Montana. It extends approximately 597.576 miles (961.705 km) from the Idaho state line east to the North Dakota state line, the greatest distance that US 12 traverses through any state.

US 12 in Montana has been defined as the Lewis and Clark Highway^[2] despite not being the route followed by Lewis and Clark across the state.

^ Road Inventory and Mapping Section (2013). Montana Road Log (PDF). Helena: Montana Department of Transportation. pp. 11–12, 19–20, 59–62, 143–144, 157–159. Archived from the original (PDF) on January 1, 2020. Retrieved November 27, 2020.
^ Montana Legislature (1947). "60-1-202: Lewis And Clark Highway". Montana Code Annotated. Title 60, Chapter 1, Part 2.

[MDT-1] Road Inventory and Mapping Section (2013). Montana Road Log (PDF). Helena: Montana Department of Transportation. pp. 11–12, 19–20, 59–62, 143–144, 157–159. Archived from the original (PDF) on January 1, 2020. Retrieved November 27, 2020.

[2] Montana Legislature (1947). "60-1-202: Lewis And Clark Highway". Montana Code Annotated. Title 60, Chapter 1, Part 2.

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