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U.S. Route 12: Wikis


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U.S. Route 12 shield
U.S. Route 12
Length: 2,483[1] mi (3,996 km)
Formed: 1926[1]
West end: US 101 at Aberdeen, WA
I-5 near Chehalis, WA
I-94 at Forsyth, MT
I-29 at Summit, SD
I-94 at Minneapolis, MN
I-35W at Minneapolis, MN
I-35E at Saint Paul, MN

I-39 / I-90 at Madison, WI
I-94 at Chicago, IL
I-65 at Gary, IN
I-94 at New Buffalo, MI
I-69 at Coldwater, MI

East end: Cass Avenue in Downtown Detroit, MI
United States Numbered Highways

U.S. Route 12 or US 12 is an east–west United States highway, running from Grays Harbor on the Pacific Ocean, in the state of Washington, to downtown Detroit, for almost 2500 miles (4000 km). As a thoroughfare, it has mostly been supplanted by I-90 and I-94, but remains an important road for local travel.

The highway begins in Aberdeen, Washington at an intersection with US 101. Its eastern terminus is currently in downtown Detroit, at the corner of Michigan and Cass Avenue.


Route description



The western terminus of US 12 is located in Aberdeen, Washington. In the 1960s, a portion of US 12 was moved north to the town of Morton, when the Mossyrock Dam was built and flooded the towns of Kosmos and Riffe, along the Cowlitz River in Lewis County. A large portion of old, two-lane US 12 was replaced by Interstate 82 and Interstate 182 in the 1980s, between Yakima and the Tri-Cities, though the freeways are still cosigned with the US 12 designation. The old two-lane highway now bears the name Wine Country Road. The highway loosely follows the eastbound leg of the Lewis and Clark Expedition, between Wallula, Washington and Clarkston, Washington, thus being marked as part of the Lewis and Clark National Historic Trail. The east end of the highway in the state is at Clarkston, where the highway crosses the Snake River into Idaho at Lewiston.

The Washington section of US 12, other than a concurrency with Interstate 5, is defined at Washington Revised Code § 47.17.055.[2]


US 12 enters the state at Lewiston, crossing the Snake River from Clarkston, Washington. It ascends the Clearwater River, concurrent with US 95 for 7 miles (11 km). It reduces to a two-lane undivided highway and goes on to Orofino, continuing up the middle fork of that river to Lowell, the junction of the Lochsa and Selway Rivers. It continues up the Lochsa and climbs to Lolo Pass at the Montana border. This portion of the highway is also designated as part of the Lewis and Clark National Historic Trail. Most of the highway in Idaho is within the Clearwater National Forest. The eastern section of US 12, through remote mountain forest and up to Lolo Pass, was built in the early 1960s, making US 12 the last US highway constructed. No services are available between Lowell and Powell, about 70 miles (112 km) further east.


US 12 enters Montana Lolo Pass, 7 miles (11 km) southwest of Lolo Hot Springs in the Lolo National Forest. After passing Lolo Peak to the south and traveling east for 33 miles (53 km), it meets with US 93 at Lolo and continues as a concurrency northeast for 11 miles (18 km), until it meets with Interstate 90 in Missoula. It then overlaps I-90 for 69 miles (111 km), until Garrison, where it heads east through Avon and Elliston. Here US 12 passes through the Helena National Forest and then on to the capital, Helena, where it junctions with Interstate 15 and US 287. It then overlaps US 287 and heads southeast, toward Townsend, where it splits off and heads east until it meets with US 89. It overlaps US 89 for 11 miles (18 km), until just past White Sulphur Springs, where it continues east on its own for 233 miles (375 km), until the junction with Interstate 94 at Forsyth. The major junctions along the way are US 191 at Harlowton and US 87 at Roundup. At exit 93 near Forsyth, US 12 overlaps I-94 for 48 miles (77 km), until Miles City, where it again splits off on its own and heads east for 89 miles (143 km) to southwestern North Dakota, passing through Baker on the way.

North Dakota

US 12 is a two-lane undivided highway that runs 87.47 miles (140.8 km), through Adams, Bowman and Slope counties in southwest North Dakota. The speed limit is 65 mph (105 km/h) on rural segments, with slower posted speeds within the cities of Marmarth, Rhame, Bowman, Scranton and Hettinger. US 12 meets with US 85 in Bowman, the routes are concurrent for a short distance through the city.

South Dakota

US 12 enters South Dakota from North Dakota, as a rural two lane highway about 10 miles (16 km) west/northwest of Lemmon. For approximately the next 70 miles (113 km), US 12 runs parallel to the border of North Dakota, sometimes within less than a mile. At Walker, US 12 heads southeast for 37 miles (60 km), where it crosses the Missouri River at Mobridge. From there it continues east for 18 miles (29 km), until it meets with US 83 near Selby. It overlaps US 83 for 7 miles (11 km) and for about half of that distance, it is an expressway. After leaving US 83, it turns due east and spends about 80 miles (129 km) as a rural two lane highway again. A few miles before reaching Aberdeen, it becomes an at-grade expressway. After the junction with U.S. Route 281, it goes back to being two lane for a few miles, before once again becoming a 4 lane expressway, until 2 miles (3 km) before Waubay. It then meets with Interstate 29 near Summit. From there it is heads southeast 22 miles (35 km), until Milbank. At Milbank, it turns back northeast for 10 miles (16 km), until it crosses into Minnesota at Big Stone City, just south of Big Stone Lake.

Legal Definition

The South Dakota section of US 12 is defined at South Dakota Codified Laws § 31-4-132.[3]


From the South Dakota/Minnesota state line at Ortonville, to Wayzata, US 12 is mostly a rural two-lane highway with a 55 mph (89 km/h) speed limit, with slower speed limits through towns and a four-lane surface arterial segment through the city of Willmar. From western Wayzata to Interstate 394 in Minnetonka, US 12 is a six-lane freeway. East of I-494, US 12 is invisibly concurrent with Interstates 394 and 94 through Minneapolis and St. Paul to the Minnesota/Wisconsin state line at Hudson.

The Minnesota section of US 12 is defined as Routes 149, 26, and 10 in Minnesota Statutes §§ 161.115(80) and 161.114(2).[4][5]


From Elkhorn, Wisconsin to near the Illinois/Wisconsin state line, U.S. 12 is a freeway with a 65 mph (105 km/h) speed limit. It continues as a two-lane highway until it approaches the city of Whitewater, where a new bypass has been constructed. It is currently two lane, but can be expanded to four lanes. U.S. 12 continues west to Madison. As US 12 nears Madison, it merges with US 14, US 151 and US 18, to form the West Beltline Highway, a four to six-lane freeway that encircles the south and west portions of the city, with a speed limit of 55 mph (90 km/h).

From Middleton, the highway continues, on a 15 mile (24 km) four-lane road completed in 2004, to cross the Wisconsin River at Sauk City.


In Illinois, US 12 is an arterial surface road that runs from Richmond, southeast to Des Plaines. It then turns due south through the Chicago metropolitan area, joining with U.S. Route 45. In Stone Park, U.S. Route 20 joins U.S. 12/45. In Hickory Hills, U.S. 45 continues south, while U.S. 12/20 runs due east in the southwest suburbs. From Hickory Hills, U.S. 12/20 runs east nearly to the Lake Michigan lakefront and then joins with U.S. Route 41, as all three routes travel southeast into the state of Indiana.

US 12 is referred to as Rand Road in Chicago's northwest suburbs. Rand is an original name for the area around Des Plaines, Illinois, the location where the road resumes its westerly direction. South of Des Plaines, U.S. 12 follows Mannheim Road and then 95th Street, before merging with U.S. 41 on Ewing and Indianapolis Avenues toward the Indiana state line.


In Indiana, US 12 is a historically significant route, that winds along the southern coast of Lake Michigan. It runs from an interchange with the Indiana Toll Road, concurrent with US Routes 20 and 41 in Whiting, to Michiana Shores, at the Michigan state line. A large portion of this segment is known as the Dunes Highway.


US 12 is now the only U.S. highway route still serving downtown Detroit, whose street grid was laid by Augustus B. Woodward, to have a five-way intersection of the roads that would become US 12, US 10, US 16, US 112 and US 25. US 24 still travels through Detroit from Puritan to 8 Mile Road on the far-west-side.

As from the earliest days of its existence, US 12 enters Michigan from Indiana, southwest of New Buffalo and continues to the old junction of US 12 and US 112 in New Buffalo. It is now assigned between New Buffalo and Detroit (except through Ypsilanti), along what was US 112 until 1962.


Since the highway's creation in 1926, the eastern terminus has always remained within a few blocks of this point.[6]

  • 1926: Cadillac Square at the convergence with US-10, US-16, US-25 and US-112. U.S. 12 goes along Grand River. The original ending was at Miles City, Montana.
  • 1939: AASHTO approved a request to extend U.S. 12 to Yellowstone National Park.
  • 1956: U.S. 12 was rerouted along the Lodge Freeway, ending on Jefferson; the terminus moved four blocks southeast, to the corner of Woodward Avenue (US-10) and Jefferson Avenue.
  • 1959: Extended to Missoula, Montana.
  • 1962: After I-94 is completed across Michigan, it is no longer co-signed with US-12. The US-12 route designation is moved to the former route of US-112, which is decommissioned. US-12 now runs along Michigan Avenue and again ends at Cadillac Square. It was extended to Lewiston, Idaho.
  • 1969: Extended to Aberdeen, Washington, to its present terminus at U.S. Route 101.
  • 1970: US-10 is rerouted from Woodward to the Lodge Freeway and Jefferson. At this time U.S. 12 apparently is extended along Woodward, to again terminate with US-10 at Woodward and Jefferson, though with the designations flip-flopped from their 1956 routing.
  • 2001: The City of Detroit and the Michigan Department of Transportation, in a series of jurisdictional transfers, move the terminus back four blocks, to again be at Cadillac Square.
  • 2005: In another transfer, the U.S. 12 terminus is truncated another four blocks, to end at the Patrick V. McNamara Federal Building, on the corner of Michigan and Cass Avenues.

The western terminus was gradually extended westward, until it met up with the Pacific Ocean.[7]

Former ferry crossing

In 1925, U.S. 12 in Michigan was originally proposed to run from Detroit to Ludington, across Lake Michigan, via the Pere Marquette Railway car ferry to Manitowoc, Wisconsin and then continuing into Wisconsin, on what later became US-10, in those two states. Also, U.S. 12 originally went into Wyoming, before being rerouted into Montana and was proposed to go into Oregon, but did not.

Chicago freeway

U.S. 12 was originally planned to be a freeway from Chicago to Madison, Wisconsin. The portion from Genoa City, WI, to Elkhorn, WI was already being built when the Interstate system was announced. After the Interstate program was announced and due to the fact that Wisconsin was not able to obtain some right-of-way land north of Elkhorn, construction was stopped. Since construction was stopped, Illinois never built any of it, but the rough grading and off-ramps are still there in Illinois. In Elkhorn, the ramps also continue past the intersection where the construction stopped, but they are not used. Much of U.S. 12 in Illinois is a divided highway and it is surface road.

See also

Related US Routes

Notes and references

  1. ^ a b Droz, Robert V. U.S. Highways : From US 1 to (US 830). URL accessed 27 February 2006.
  2. ^ Washington Revised Code § 47.17.055
  3. ^ South Dakota Statute Chapter 31-4 § 132
  4. ^ Minnesota Statutes § 161.115
  5. ^ Minnesota Statutes §161.114
  6. ^ Bessert, Christopher J.. "US-12".  
  7. ^ Weingroff, Richard F. (2005-05-07). "U.S. 12 Michigan to Washington". Federal Highway Administration.  

External links

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