Wikipedia

Interstate 90 in Montana

This article is about the section of Interstate 90 in Montana. For the entire route, see Interstate 90.

Interstate 90 (I-90) is an east–west transcontinental Interstate Highway across the northern United States, linking Seattle to Boston. The portion in the state of Montana is 552.54 miles (889.23 km) in length, passing through 14 counties in central and southern Montana. It is the longest segment of I-90 within a single state.[2]

Interstate 90 marker
Interstate 90
Map
I-90 highlighted in red
Route information
Maintained by MDT
Length552.46 mi[1] (889.10 km)
Existed1957–present
HistoryCompleted in 1987
NHSEntire route
Major junctions
West end I-90 at Idaho state line
Major intersections
East end I-90 / US 87 at Wyoming state line
Location
CountryUnited States
StateMontana
CountiesMineral, Missoula, Granite, Powell, Deer Lodge, Silver Bow, Jefferson, Broadwater, Gallatin, Park, Sweet Grass, Stillwater, Yellowstone, Big Horn
Highway system
← US 89→ US 93

Route description

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Mineral County

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I-90 enters Montana and Mineral County from Shoshone County, Idaho over the 4,725-foot (1,440 m) high Lookout Pass, which traverses the Coeur d'Alene Mountains of the Bitterroot Range, and immediately has its first interchange, a partial cloverleaf interchange serving extreme northwest Mineral County and access to Lookout Pass Ski and Recreation Area. The highway continues southeasterly through woodlands, paralleling the St. Regis River, before meeting the Dena Mora (Lookout Pass) rest area 4.7 miles (7.6 km) east of the Idaho–Montana border.[3] About 0.5 miles (0.80 km) from the rest stop is a diamond interchange, serving a small minor road into the St. Joe National Forest in Idaho.

The highway continues, winding through the woodlands until another diamond interchange, serving the small unincorporated community of Saltese. Continuing east for about six miles (9.7 km), each direction diverges for a small distance before returning side to side for a diamond interchange serving the unincorporated community of Haugan.[4][5]

Two miles (3.2 km) after Haugan, I-90 intersects the census-designated place (CDP) of De Borgia, continuing southeasterly, intersecting several minor roads, before reaching the CDP of St. Regis and Montana Highway 135 (MT 135). The highway stops paralleling the St. Regis River, and begins to parallel, and cross over several times, the Clark Fork River. Superior, the county seat, is intersected before the highway turns south through the Quartz Flats rest area, located 58.2 miles (93.7 km) from the Idaho border.[3] After leaving the rest area, the highway straightens out, heading easterly. The highway continues east before exiting the county, just south of Alberton.[4][5]

Missoula, Granite, and Powell counties

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I-90 in Granite County, facing east

Entering Missoula County, the highway intersects Alberton, before continuing easterly through Huson and Secondary Highway 263 (S-263). The highway continues southeast before intersecting the concurrent highways US Highway 93 (US 93) and MT 200, which join I-90 from the west. The three highways continue into the county seat of Missoula, where, at the first exit, US 93 leaves on the western border of Missoula and travels through Orchard Homes. The next two exits travel into Downtown Missoula, while the last exit serves East Missoula. US 12 joins I-90 and MT 200 exits to the north of the highway outside of Missoula, paralleling the Blackfoot River as I-90 continues east, following and then intersecting S-210 in Clinton. The Bearmouth rest area, 142.8 miles (229.8 km) from the Idaho border, is intersected before crossing the Missoula–Granite county border.[3][4][5]

After entering Granite County, I-90 has an interchange with an access road to the Garnet Back Country Byway,[6] providing access to the Garnet Range on the west slope of the Rocky Mountains. The highway passes north of Lolo National Forest while headed easterly. The highway continues through northern Granite county, intersecting MT 1 before exiting the county entering Powell County. I-90 intersects S-272 13 miles (21 km) after entering the county, which clips the eastern segment of Lolo National Forest, before the seasonal Gold Creek rest area is intersected.[3] Garrison is northeast of the highway as US 12 ends its concurrency, traveling north from I-90 toward the state capital of Helena. I-90 turns south, paralleling former Northern Pacific Railway trackage,[7] before intersecting S-275 and the county seat, Deer Lodge. Continuing south, I-90 exits Powell County at Racetrack.[4][5]

Deer Lodge, Silver Bow, and Jefferson counties

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I-90 bisects the northern tip of Deer Lodge County, in a southwesterly direction. Galen and S-273 are intersected, before the highway passes west of the Warm Springs State Wildlife Management Area. After passing the wildlife management area, the highway passes by Warm Springs and MT 48. Just northwest of the Deer Lodge–Silver Bow county border, I-90 intersects MT 1.[4][5]

Fairmont Hot Springs Resort, accessible via S-441, is the first exit in Silver Bow County on I-90, as the highway starts to turn back toward the east. Ramsay is located in the southwest corner of the interchange where I-15 becomes concurrent with I-90 through Butte. On the western edge of Butte, I-115 continues east into town, as I-15/I-90 turns southeast, bypassing most of downtown Butte. An interchange with MT 2 serves Bert Mooney Airport before I-15/I-90 split just east of Butte, with I-15 continuing north over the Continental Divide over the 6,368-foot (1,941 m) high Elk Park Pass, which straddles the Silver Bow–Jefferson county border. I-90 heads south then east, also entering Jefferson County, passing over the divide at Homestake Pass which is 6,375-foot (1,943 m) high. After traveling the pass, an emergency escape ramp can be found on the highway's eastbound lanes. Jefferson County has interchanges with S-399 east of Pipestone, Montana and S-359 east of Cardwell before meeting the Jefferson–Broadwater county border.[4][5]

Broadwater, Gallatin, and Park counties

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I-90 through Bozeman Pass

There is only one exit along I-90 in Broadwater County, linking MT 2 in the south and US 287 north of the highway before crossing the Broadwater–Gallatin county border at the Missouri River. I-90 parallels S-205, bypassing the towns of Trident, Logan, Manhattan, and Belgrade on the north of the highway. A new interchange was constructed just east of Belgrade (exit 299) that services Bozeman Yellowstone International Airport to the north and the western area of the city of Bozeman. MT 85 travels south from I-90 in Belgrade, providing access to Bozeman Hot Springs. The highway then enters the city of Bozeman, the county seat, and intersects and becomes concurrent with US 191. I-90 exits the county at the Gallatin–Park county border at 5,760-foot (1,760 m) high Bozeman Pass. US 89 intersects I-90 in the county seat of Livingston and passes over the Yellowstone River. The highway continues northeasterly, paralleling the river, intersecting S-295 before crossing the Park–Sweet Grass county border.[4][5]

Sweet Grass and Stillwater counties

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West of Park City facing west

Still paralleling the Yellowstone River, I-90 travels northwest intersecting S-298 and US 191 in the county seat of Big Timber. The highway turns back southeast, passing south of Greycliff and the Greycliff rest area, located 380.9 miles (613.0 km) from the Idaho border.[3] The highway passes through the Sweet Grass–Stillwater county border just west of Reed Point. After passing into Stillwater County, I-90 crosses over the river, and enters the county seat of Columbus, intersecting MT 78 south of the highway and S-306 on the north side of the highway. The highway is titled the Robert E. Ewing Jr. Memorial Highway between mileposts 410 and 424.[8] I-90 intersects the Columbus rest area, 418.8 miles (674.0 km) from the Idaho border,[3] followed by Park City before exiting Stillwater County.[4][5]

Yellowstone and Big Horn counties

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US 212 becomes concurrent with I-90 just east of Laurel before entering the county seat of Billings. I-90 Business (I-90 Bus.) passes into town as the main freeway travels south of Billings and bisects Billings Heights and Lockwood intersecting MT 3 and US 87, which joins the I-90/US 212 concurrency. On the extreme eastern end of Billings, the three highways intersect the western terminus of I-94, which heads northeast toward North Dakota, while I-90 turns southeast into Big Horn County. Immediately after entering Big Horn County, the three highways pass the seasonal Hardin rest area.[3] Entering Hardin, the county seat, the three highways intersect S-313 and MT 47. S-313 provides access to Yellowtail Dam, while MT 47 connects back to I-94. After exiting Hardin, I-90 turns south, entering the Crow Indian Reservation and intersects S-384, before reaching Crow Agency. Crow Agency is home to Little Bighorn Battlefield National Monument and Reno–Benteen Battlefield Memorial, which are passed after US 212 departs to the east. Continuing south, I-90/US 87 parallels S-451 and the Little Bighorn River, passing by Garryowen, Benteen, Lodge Grass, and Wyola before exiting the state of Montana and entering Sheridan County, Wyoming.[4][5]

History

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I-90 replaced US 10 between Livingston and the Idaho border,[9] and, before that, the Yellowstone Trail.[10] Some sections of the highway follow the historic Mullan Road, a military road constructed from 1859 to 1862 between Fort Walla Walla in modern-day Washington and Fort Benton in Montana.[11]

The section over Homestake Pass cost $18.5 million (equivalent to $133 million in 2023[12]) to construct and was completed on October 30, 1966.[13] The final two-lane section of the highway, near Springdale, was expanded to four lanes in May 1987.[14]

Until 1995 in Montana near the Idaho border, I-90 was not a divided highway for a few stretches, having only a narrow paved median.

From 1995 until 1999, the daytime maximum speed limit in Montana was "reasonable and prudent". As of October 1, 2015, the daytime and nighttime speed limits on Interstate Highways are 80 mph (130 km/h) for cars and light trucks and 65 mph (105 km/h) for heavy trucks, except within urban areas, where the maximum speed limit is 65 mph (105 km/h) for all vehicles, day or night.[15][16] The western 34 miles (55 km) have a lower speed limit, as well as the Missoula and Butte urban areas.[17]

In 1996, a section of I-90 was closed for 19 days due to a train derailment and chlorine spill near Alberton.[18]

Expansion of the Billings area corridor

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The 2012 Billings area I-90 corridor planning study recommends many improvements to the corridor from Laurel through Lockwood, including construction of new east and westbound bridges over the Yellowstone River, with each bridge having three to four traffic lanes. Also recommended are construction of additional eastbound and westbound traffic lanes from Shiloh to Johnson Lane and reconstruction and widening of many of the bridges, interchanges and on/offramps along the corridor at an estimated cost of $114 million.[19]

Exit list

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CountyLocationmi[20]kmExitDestinationsNotes
MineralLookout Pass0.0000.000 
  I-90 west – Coeur d'Alene, Spokane		Continuation into Idaho
0.0770.1240Lookout PassLookout Pass Ski and Recreation Area
Taft5.5808.9805Taftaccess to St. Regis (Sohon)/Mullan Pass, St. Paul Pass Tunnel, and Route of the Hiawatha rail trail
Saltese10.41816.76610Saltese
Haugan16.54126.62016Haugan
De Borgia18.75230.17818De Borgia
Henderson21.82035.11622HendersonOld Mullan Road/Mullan Gulch Road to St. Regis
Drexel25.21640.58125Drexel
​26.20742.17626Ward Creek RoadEastbound exit and entrance
​29.94048.18430Two Mile Road
St. Regis33.24053.49533  MT 135 – St. Regisseasonal access to Avery via the St. Joe River Scenic Byway[21]
Sloway37.01659.57137Sloway Area
​42.24767.99043Dry Creek Road
Superior46.75175.23847  S-257 – Superiorseasonal access to Headquarters
Lozeau54.65387.95555Lozeau, Quartz
Tarkio60.97198.12361Tarkio
Crystal Springs64.818–
65.565		104.314–
105.517		65Crystal Springs
​66.055106.30566Fish Creek Road
Cyr69.483111.82270CyrWestbound exit and eastbound entrance
​74.328119.61975 
  I-90 BL east – Alberton
MissoulaAlberton76.809123.61277 
   I-90 BL west / S-507 (Petty Creek Road) – Alberton
​81.765131.58882Nine Mile Road
Huson84.325135.70885  S-574 – Huson
Frenchtown88.888143.05189  S-263 – FrenchtownMullan Road to Missoula
Wye95.483153.66596 
  
  US 93 north / MT 200 west – Kalispell		West end of US 93 / MT 200 overlap
​99.091159.47299Airway Boulevard
Missoula100.867162.330101 
  
  I-90 BL east / US 93 south (Reserve Street) – Hamilton		East end of US 93 overlap
103.930167.259104Orange Street
104.794168.650105 
  
  I-90 BL west / US 12 west (Van Buren Street)		West end of US 12 overlap
106.419171.265107East Missoula
Bonner109.634176.439109 
  MT 200 east – Bonner, Great Falls		East end of MT 200 overlap
Turah113.519182.691113Turah
Clinton120.423193.802120Clinton
Rock Creek125.475201.932126Rock Creek RoadRock Creek Road Scenic Byway
​129.868209.002130Beavertail Road
GraniteBearmouth137.524221.323138Bearmouth Area
Drummond152.802245.911153  MT 1 – Drummond, PhilipsburgEastbound exit and westbound entrance
153.727247.400154 
  To MT 1 – Drummond, Philipsburg		Westbound exit and eastbound entrance
PowellJens161.637260.130162Jens
Gold Creek165.360266.121166Gold Creek
Phosphate169.327272.505170Phosphate
Garrison173.471279.175174 
  US 12 east – Garrison, Helena		East end of US 12 overlap; Eastbound exit and westbound entrance
174.656281.082175 
 
  To US 12 east – Garrison, Helena		No westbound entrance
​178.245286.858179Beck Hill Road
Deer Lodge183.625295.516184 
  I-90 BL east – Deer Lodge
​186.640300.368187 
  I-90 BL west – Deer Lodge		No westbound entrance
Racetrack193.861311.989195Racetrack
Deer LodgeGalen196.271315.868197  S-273 – Galen
Warm Springs200.264322.294201  MT 48 – Warm Springs
Opportunity206.336332.066208  MT 1 – Anaconda, Opportunity
Silver Bow​209.806337.650211  S-441 – Gregson, Fairmont Hot Springs
Ramsay214.860345.784216Ramsay
Nissler217.337349.770219 
  I-15 south – Dillon, Idaho Falls		West end of I-15 overlap; I-15 exit 121
Rocker218.408351.494122[a]Rocker
Butte220.237354.437124[a] 
  
  
  I-115 east / I-15 BL north / I-90 BL east – City Center		Eastbound exit and westbound entrance
222.263357.698126[a]Montana Street
223.883360.305127[a] 
  
  I-15 BL south / I-90 BL west (Harrison Avenue)		Signed as exits 127A and 127B eastbound; I-15 Bus./I-90 Bus. not signed eastbound
224.933361.995227 
  I-15 north – Helena		East end of I-15 overlap; I-15 exit 129
226.785364.975228Continental Drive
Homestake231.425372.442233Homestake
JeffersonPipestone240.144386.474241Pipestone
Whitehall247.203397.835249  
  MT 55 to MT 69 – Whitehall		S-399 (Whitetail Road) north from this exit
Cardwell254.472409.533256  S-359 – Cardwell, Boulder
​265.878427.889267Milligan Canyon Road
Broadwater​272.975439.311274  US 287 – Helena, Ennis
GallatinThree Forks276.514445.006278   MT 2 / S-205 – Three Forks, Trident
Logan281.447452.945283Logan, Trident
Manhattan286.871461.674288  
  S-288 to S-346 – Manhattan, Amsterdam
Belgrade296.474477.129298   MT 85 / S-291 – Amsterdam, Belgrade, West Yellowstone
297.280478.426299Airway Boulevard
Bozeman303.434488.330305  S-412 (North 19th Avenue) / Springhill Road
305.084490.985306 
   
 
  I-90 BL east / S-205 (North 7th Avenue) to US 191 south
307.568494.983309 
  
  I-90 BL west / US 191 south (Main Street)		West end of US 191 overlap
​311.207500.839313Bear Canyon Road
​314.528506.184316Trail Creek Road
​317.428510.851319Jackson Creek Road
​322.387518.832324Ranch Access
ParkLivingston328.850529.233330 
  I-90 BL east – Livingston
330.804532.377333 
  US 89 south – Yellowstone National Park, Livingston City Center		West end of US 89 overlap
335.752540.340337 
  I-90 BL west – Livingston
​338.282544.412340 
  US 89 north – White Sulphur Springs		East end of US 89 overlap
​341.144549.018343Mission Creek Road
​348.308560.547350East End Access
​350.562564.175352Ranch Access
Sweet Grass​352.169566.761354  S-563 – Springdale
​359.952579.287362De Hart
​365.541588.281367 
  
  I-90 BL east / US 191 north – Big Timber, Harlowton		East end of US 191 overlap
​368.691593.351370 
  
 
  I-90 BL west to US 191 north – Big Timber, Harlowton
​375.932605.004377Greycliff
​382.929616.264384Bridger Creek Road
Stillwater​390.017627.672392Reed Point
​394.893635.519396Ranch Access
​398.526641.365400Springtime Road
​406.813654.702408  MT 78 – Columbus
​424.583683.300426Park City
YellowstoneLaurel430.920693.499432 
  I-90 BL east – West Laurel
432.039695.299434 
   US 212 west / US 310 – Laurel, Red Lodge		West end of US 212 overlap
435.439700.771437 
  I-90 BL west / South Frontage Road – East Laurel
Billings441.444710.435443Zoo Drive, Shiloh Road
443.910714.404446 
  I-90 BL east / King Avenue West, Mullowney Lane – West Billings
445.150716.399447South Billings Boulevard – Billings City Center
448.056721.076450  MT 3 (27th Street) – Billings City Center
450.817725.520452 
  
  I-90 BL west / US 87 north – Roundup, Billings Heights, Lockwood		West end of US 87 overlap
453.263729.456455Johnson Lane – Lockwood
454.264731.067456 
  I-94 east – Miles City, Bismarck		I-94 west to 90 east exit 0; western terminus of I-94
​460.132740.511462Pryor Creek Road
​467.594752.520469Arrow Creek Road
Big Horn​476.564766.955478Fly Creek Road
​482.327776.230484Frontage Road – Toluca
Hardin493.863794.795495 
   I-90 BL east / MT 47 – Hardin City Center
495.455797.358497 
  I-90 BL west (Third Street) – Hardin
​501.149806.521503Dunmore
​507.093816.087509Crow Agency
​508.758818.767510 
  US 212 east – Little Bighorn Battlefield, Broadus		East end of US 212 overlap
​512.638825.011514Garryowen
​528.564850.641530  S-463 – Lodge Grass
​541.924872.142544Wyola
​547.796881.592549Aberdeen
​554.105891.746 
  
  I-90 east / US 87 south – Sheridan, Rapid City		Continuation into Wyoming
1.000 mi = 1.609 km; 1.000 km = 0.621 mi
  1. ^ a b c d Exit numbers follow I-15

See also

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References

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  1. ^ Starks, Edward (January 27, 2022). "Table 1: Main Routes of the Dwight D. Eisenhower National System of Interstate and Defense Highways". FHWA Route Log and Finder List. Federal Highway Administration. Retrieved September 16, 2022.
  2. ^ Rand McNally (2023). "United States" (Map). Rand McNally Road Atlas: United States (2024 ed.). 1:9,820,800. Chicago: Rand McNally. pp. 2–3. ISBN 978-0-528-02718-5.
  3. ^ a b c d e f g Montana Department of Transportation. Montana Rest Areas (Map). Montana Department of Transportation. Retrieved November 8, 2010.
  4. ^ a b c d e f g h i Rand McNally (2009). "Montana" (Map). The Road Atlas. c. 1:1,900,800. Chicago: Rand McNally. pp. 60–61. ISBN 978-0-528-94219-8.
  5. ^ a b c d e f g h i Montana Department of Transportation (2009). Montana Highway Map (PDF) (Map). Helena: Montana Department of Transportation.
  6. ^ "Garnet Back Country Byway". America's Byways. Federal Highway Administration. Archived from the original on August 27, 2010. Retrieved November 9, 2010.
  7. ^ United States Geological Survey (April 1903). Helena Quadrangle (Map). 1:250,000. Reston, Virginia: United States Geological Survey. Retrieved November 9, 2010.
  8. ^ "60-1-213. Robert E. Ewing Jr. memorial highway". Montana Code Annotated 2009. Montana Legislature. 2007. Archived from the original on March 23, 2010. Retrieved November 10, 2010.
  9. ^ Meeks, Harold (2000). On the Road to Yellowstone: The Yellowstone Trail and American Highways, 1900–1930. Missoula, Montana: Pictorial Histories Publishing. p. 127. ISBN 1-57510-079-7.
  10. ^ Rand McNally (1926). "Montana" (Map). Junior Road Map. Scale not given. Chicago: Rand McNally.
  11. ^ Geranios, Nicholas K. (June 15, 2003). "Little-Known Road Played Big Role in Conquest of the West". Los Angeles Times. Associated Press. p. A28. Retrieved October 3, 2018.
  12. ^ Johnston, Louis; Williamson, Samuel H. (2023). "What Was the U.S. GDP Then?". MeasuringWorth. Retrieved November 30, 2023. United States Gross Domestic Product deflator figures follow the MeasuringWorth series.
  13. ^ Axline, Jon (Autumn 2013). "A Massive Undertaking: Construction Montana's Interstate Highways, 1956–1988". Montana: The Magazine of Western History. Vol. 63, no. 3. Montana Historical Society. p. 60. ISSN 0026-9891. JSTOR 24416216. OCLC 1051147215.
  14. ^ "I-90 finished in state". Billings Gazette. May 14, 1987. p. 1C. Retrieved September 24, 2018 – via Newspapers.com.
  15. ^ Montana Department of Transportation. "Speed Limits in Montana". Montana Department of Transportation. Retrieved September 19, 2018.
  16. ^ Dennison, Mike (May 5, 2015). "New law will increase some highway speed limits to 80 mph". The Billings Gazette.
  17. ^ Briggeman, Kim (September 28, 2015). "80 mph: Speed limit to increase on most – but not all – interstates in Montana". The Missoulan. Retrieved September 19, 2018.
  18. ^ Kato, Dillon (May 3, 2015). "Workshop Uses 1996 Alberton Chlorine Spill to Teach Emergency Management]". Missoulian.
  19. ^ "Billings Area I-90 Corridor Planning Study". Retrieved January 29, 2013.
  20. ^ Montana Department of Transportation (2013). Montana Road Log (PDF). Montana Department of Transportation. pp. 9–18. Retrieved April 4, 2015.
  21. ^ "The St. Joe River Scenic Byway in Idaho & Montana". Big Sky Fishing. Retrieved May 14, 2017.
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