Interstate 90 in Montana

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

Interstate 90
Riverbend North
Route information
Maintained by MDT
Length:	551.68 mi (887.84 km)
Major junctions
West end:	I-90 at Idaho state line
	I-15 in Butte I-115 in Butte I-94 in Billings
East end:	I-90 / US 87 at Wyoming state line
Location
Counties:	Mineral, Missoula, Granite, Powell, Deer Lodge, Silver Bow, Jefferson, Broadwater, Gallatin, Park, Sweet Grass, Stillwater, Yellowstone, Big Horn
Highway system
Main route of the Interstate Highway System Main • Auxiliary • Business Montana Highways ← MT 89 US 91 →

Interstate 90 in Montana (I-90) is a portion of the east–west transcontinental Interstate 90, which links Seattle, Washington to Boston, Massachusetts. The portion in the U.S. state of Montana is 551.68 miles (887.84 km) long, linking fourteen counties through central and southern Montana.

Route description

Mineral County

Interstate 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'Alène Mountains of the Bitterroot Range, and immediately has its first interchange, a partial cloverleaf serving extreme northwest Mineral County. The highway continues southeasterly through woodlands, paralleling the St. Regis River, before meeting the Dena Mora (Lookout Pass) rest area 4.7 mi (7.6 km) east of the Idaho–Montana border. About a ¹⁄₂ mi (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 6 mi (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.

Two miles (3.22 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 mi (93.7 km) from the Idaho border. After leaving the rest area, the highway straightens out, heading easterly. The highway continues east before exiting the county, just south of Alberton.

Missoula, Granite and Powell Counties

I-90 in Granite County, facing east

Entering Missoula County, the highway intersects Alberton, before continuing easterly through Hudson and MT 263. The highway continues southeast before intersecting the concurrent highways U.S. Route 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 Montana Secondary Highway 210 (S-210) in Clinton. The Bearmouth rest area, 142.8 mi (229.8 km) from the Idaho border is intersected before crossing the Missoula–Granite County border.

After entering Granite County, I-90 has an interchange with an access road to the Garnet Back Country Byway, providing access to the Garnet Range on the west slope of the Rocky Mountains. The highway passes north of the Lolo National Forest while headed easterly. The highway continues through northern Granite county, intersecting MT 1 before exiting the county entering Powell County. Thirteen miles (29.92 km) after entering the county, I-90 intersects MT 272, which clips the eastern segment of the Lolo National Forest, before the seasonal Gold Creek rest area is intersected. Garrison is northeast of the highway as US 12 ends its concurrency, traveling north from I-90 towards the state capital of Helena. I-90 turns south, paralleling former Northern Pacific Railway trackage, before intersecting S-275 and the county seat, Deer Lodge. Continuing south, Dempsey is the final city intersected by I-90 before entering Deer Lodge County.

Deer Lodge, Silver Bow and Jefferson Counties

Interstate 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.

Fairmont Hot Springs, accessible via S-441 is the first exit in Silver Bow County on I-90, as the highway starts to turn back towards the east. Ramsey 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-15/90 turns southeast, bypassing most of downtown Butte. An interchange with MT 2 serves the Bert Mooney Airport before I-15/90 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. Jefferson County has interchanges with S-399 east of Pipestone and S-359 east of Cardwell before meeting the Jefferson–Broadwater County border.

Broadwater, Gallatin and Park Counties

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. 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. Intersecting and traveling north from I-90 is MT 86 providing access to Bridger Bowl Ski Area. 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 passing over the Yellowstone River. The highway continues northeasterly, paralleling the river, intersecting S-295 before crossing the Park–Sweet Grass County border.

Sweet Grass and Stillwater Counties

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 mi (613.0 km) from the Idaho border. 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. I-90 intersects the Columbus rest area, 418.8 mi (674.0 km) from the Idaho border, followed by Park City before exiting Stillwater County.

Yellowstone and Big Horn Counties

US 212 becomes concurrent with I-90 just east of Laurel before entering the county seat of Billings. I-90 Bus. passes into town as the main freeway travels south of Billings, 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 beginning of I-94, which heads northeast towards 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. 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 the 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.

History

Old style I-90 shield

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"; it is now 75 miles per hour (121 km/h). On I-90, at Exit 0 (right on the MT/ID border) is the Lookout Pass Ski Area, one exit east of there is the Hiawatha Trail (rails-to-trails).

Interstate 90 replaced US 10 between Livingston and the Idaho border, and before that, the Yellowstone Trail.

Exit list

County	Location	Mile	#	Destinations	Notes
Mineral			0	Lookout Pass
			5	Taft Area
			10	Saltese
			16	Haugan
			18	De Borgia
			22	Henderson
			25	Drexel
			26	Ward Creek Road	Eastbound exit and entrance
			30	Two Mile Road
			33	MT 135 – St. Regis
			37	Sloway Area
			43	Dry Creek Road
	Superior		47	S-257 – Superior
			55	Lozeau, Quartz
			61	Tarkio
			66	Fish Creek Road
			70	Cyr	Westbound exit and eastbound entrance
	Alberton		75	Alberton
Missoula			77	S-507 (Petty Creek Road) – Alberton
			82	Nine Mile Road
			85	Huson
			89	Frenchtown
			96	US 93 north / MT 200 west – Kalispell	West end of US 93/MT 200 overlap
			99	Airway Boulevard
	Missoula		101	I-90 Bus. east / US 93 south (Reserve Street) – Hamilton	East end of US 93 overlap
			104	Orange Street
			105	I-90 Bus. west / US 12 west (Van Buren Street)	West end of US 12 overlap
			107	East Missoula
			109	MT 200 east – Bonner, Great Falls	East end of MT 200 overlap
			113	Turah
			120	Clinton
			126	Rock Creek Road
Granite			130	Beavertail Road
			138	Bearmouth Area
	Drummond		153	MT 1 – Drummond, Philipsburg	Eastbound exit and westbound entrance
			154	To MT 1 – Drummond, Philipsburg	Westbound exit and eastbound entrance
Powell			162	Jens
			166	Gold Creek
			170	Phosphate
			174	US 12 east – Garrison, Helena	East end of US 12 overlap; eastbound exit and westbound entrance
			175	To US 12 east – Garrison, Helena	No westbound entrance
			179	Beck Hill Road
	Deer Lodge		184	I-90 Bus. east – Deer Lodge
			187	I-90 Bus. west – Deer Lodge	No westbound entrance
			195	Racetrack
Deer Lodge			197	S-273 – Galen
			201	Warm Springs
			208	MT 1 – Anaconda, Opportunity
Silver Bow			211	S-441 – Gregson, Fairmont, Hot Springs
			216	Ramsay
			219	I-15 south – Dillon, Idaho Falls	West end of I-15 overlap
			222	Rocker
			224	I-115 east (I-15 Bus. north, I-90 Bus. east) – City Center	Eastbound exit and westbound entrance
	Butte		226	Montana Street
			227	I-15 Bus. south / I-90 Bus. west (Harrison Avenue, MT 2)	Signed as exits 127A (south) and 127B (north) eastbound
			227	I-15 north – Helena	East end of I-15 overlap
			228	Continental Drive
			233	Homestake
Jefferson			241	Pipestone
	Whitehall		249	MT 55 to MT 69 – Whitehall
			256	S-359 – Cardwell, Boulder
			267	Milligan Canyon Road
Broadwater			274	US 287 – Helena, Ennis
Gallatin			278	MT 2 / S-205 – Three Forks, Trident
			283	Logan, Trident
			288	S-288 to S-346 – Manhattan, Amsterdam
	Belgrade		298	MT 85 / S-291 – Amsterdam, Belgrade, West Yellowstone
	Bozeman		305	S-412 (North 19th Avenue) / Springhill Road
			306	I-90 Bus. east / S-205 (North 7th Avenue) to US 191 south
			309	I-90 Bus. south / US 191 (Main Street)	West end of US 191 overlap
			313	Bear Canyon Road
			316	Trail Creek Road
			319	Jackson Creek Road
			324	Ranch Access
Park			330	I-90 Bus. east – Livingston
	Livingston		333	US 89 south – Yellowstone National Park, Livingston City Center	West end of US 89 overlap
			337	I-90 Bus. west – Livingston
			340	US 89 north – White Sulphur Springs	East end of US 89 overlap
			343	Mission Creek Road
			350	East End Access
			352	Ranch Access
Sweet Grass			354	S-563 – Springdale
			362	De Hart
			367	I-90 Bus. east / US 191 north – Big Timber, Harlowton	East end of US 191 overlap
			370	I-90 Bus. west to US 191 north – Big Timber, Harlowton
			377	Greycliff
			384	Bridger Creek Road
Stillwater			392	Reed Point
			396	Ranch Access
			400	Springtime Road
			408	MT 78 – Columbus
			426	Park City
Yellowstone			433	I-90 Bus. east – West Laurel	Eastbound exit and westbound entrance
	Laurel		434	US 212 west / US 310 – Laurel, Red Lodge	West end of US 212 overlap
			437	I-90 Bus. west / South Frontage Road – East Laurel
	Billings		443	Zoo Drive
			446	I-90 Bus. east / King Avenue West, Mullowney Lane – West Billings
			447	South Billings Boulevard – Billings City Center
			450	MT 3 (27th Street) – Billings City Center
			452	I-90 Bus. west / US 87 north – Roundup, Lockwood	West end of US 87 overlap
			455	Lockwood
			456	I-94 east – Miles City, Bismarck
			462	Pryor Creek Road
			469	Arrow Creek Road
Big Horn			478	Fly Creek Road
			484	Frontage Road – Toluca
	Hardin		495	I-90 Bus. east / MT 47 – Hardin City Center
			497	I-90 Bus. west (Third Street) – Hardin
			503	Dunmore
			509	Crow Agency
			510	US 212 east – Little Bighorn Battlefield, Broadus	East end of US 212 overlap
			514	Garryowen
			530	S-463 – Lodge Grass
			544	Wyola
			549	Aberdeen

References

• Meeks, Harold (November 2000). On the road to Yellowstone: the Yellowstone Trail and American highways, 1900-1930. Missoula, Mont,: Pictoral Histories Publishing Company, Inc.. ISBN 1575100797. 

Interstate 90
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