Interstate 90 in Wyoming

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Interstate 90

I-90 highlighted in red
Route information
Maintained by WYDOT
Length208.80 mi[1] (336.03 km)
NHSEntire route
Major junctions
West end I-90 / US 87 at Montana state line
Major intersections
East end I-90 / US 14 at South Dakota state line
CountryUnited States
CountiesSheridan, Johnson, Campbell, Crook
Highway system
  • Wyoming State Highway System
US 89 WYO 90

Interstate 90 (I-90) in the US state of Wyoming traverses the northeastern corner of the state, passing through the cities and communities of Sheridan, Buffalo, and Gillette.[2]

Route description

I-90 enters Wyoming from Montana and heads south concurrent with US Highway 87 (US 87) through hilly grasslands. It curves to the southeast and meets an interchange that serves the small community of Parkman. Continuing southeast, the highway intersects US 14 at a diamond interchange. US 14 joins I-90 and US 87, and the three routes curve east. After the freeway bends back to the southeast, it intersects the eastern end of Wyoming Highway 345 (WYO 345), then crosses the BNSF Railway[3] (formerly the Chicago, Burlington and Quincy Railroad) and the Tongue River. The highway serves as the western terminus of WYO 339 and then passes over WYO 338 without an intersection just before it crosses Goose Creek. Just south of Goose Creek, US 14 and US 87 split off to the south of I-90 via a trumpet interchange. This road is also signed as a I-90 Business (I-90 Bus.).[4]

View of south Sheridan from I-90

The freeway turns due south and skirts around the eastern edge of Sheridan. It intersects WYO 336, then crosses over the BNSF Railway again,[3] before intersecting US 14 farther south. South of Sheridan, I-90 continues to travel south roughly parallel to US 87. The highway intersects WYO 342 and Prairie Dog Creek Road at diamond interchanges before US 87 merges back into and becomes concurrent with I-90. The highway runs southwest of Lake Desmet. Here, it meets Lake Ridge Road, which leads to the lake.[4]

Southeast of Lake Desmet, I-90/US 87 comes to a diamond interchange with Rock Creek Road. It then intersects US 87 Bus. and I-25 Bus. at an incomplete diamond interchange; only traffic heading southbound can exit, and traffic from the business loops can only access I-90 northbound. Just southeast of this interchange, I-90 meets the northern terminus of I-25. US 87 follows I-25 southbound toward Buffalo, while I-90 bends to the southeast and intersects US 16 at a diamond interchange.[4]

Southeast of Buffalo, I-90 continues in a general southeasterly direction through hilly grasslands. The highway intersects several minor farm roads, then curves to the northeast toward Gillette. Just west of the city, the freeway turns due east. Within Gillette, I-90 comes to a diamond interchange with WYO 50 and its own business loop, then dips to the southeast and meets another diamond interchange, this one with WYO 59. I-90 then has one last exit in Gillette: a partial cloverleaf interchange with US 14, US 16, and WYO 51. The first two of those routes become concurrent with I-90 and follow it east.[4]

I-90 westbound between Rozet and Wyodak

The freeway crosses the BNSF Railway[3] and then turns to the east. It meets a diamond interchange with Garner Lake Road, then leaves Gillette and intersects American Road before crossing the BNSF Railway again.[3] The highway travels east, parallel to WYO 51 and then meets Adon Road, then curves to the southeast toward Moorcroft. I-90 has two exits in Moorcroft; at the first exit, US 14 and US 16 leave I-90, and I-90's business loop begins. The highway passes over US 14 with no access and then meets its second exit in the city: the eastern terminus of its business loop. East of this exit, I-90 leaves the city.[4]

East of Moorcroft, I-90 intersects several more minor rural roads while it bends to the northeast toward Sundance. As it nears Sundance, it shares a diamond interchange with US 14 and I-90 Bus. The route then curves to the east and enters the city, intersecting WYO 585 at a diamond interchange. I-90 then meets US 14 and the eastern terminus of I-90 Bus.; the former becomes concurrent with I-90, and the two routes head northeast, leaving Sundance. Northeast of Sundance, I-90/US 14 parallels the former alignment of the latter. The highway intersects Sundance-Moskee Road, then bends north and meets WYO 111. I-90/US 14 then has one last exit, with Sand Creek Road, before crossing into South Dakota.[4]


During early planning of I-90, the town of Clearmont (on US 14) filed suit against the Wyoming Highway Commission for an alleged violation of a 1955 state law that required approval from voters for the construction of a bypass. The town sought an injunction to halt construction and reroute I-90 towards the town, which was 29 miles (47 km) north of the planned alignment, arguing it would be a straighter route between Sheridan and Gillette.[5] Clearmont had previously been selected for a rerouting of US 14 and US 16 in 1957, which was seen as a precursor to a later Interstate Highway; the straighter route was also supported by business groups in Sheridan.[6] The injunction was denied by a state district judge in 1959 and was appealed to the Wyoming Supreme Court, which ruled in favor of the state highway commission in December 1960.[7][8]

Construction of I-90 in northwestern Wyoming began during the appeals process, with 58 miles (93 km) under active contracts for grading and site preparation by December 1960.[8] The first section to open in Wyoming ran 6.9 miles (11.1 km) north of Sheridan and was completed in 1961.[9] The bypass of Sheridan, one of the first major sections of the freeway, was opened to traffic on July 28, 1962.[10] The longest stretch, 65 miles (105 km) between Buffalo and Gillette, was dedicated on October 14, 1962, and cost $18.4 million to construct.[11] It was initially a two-lane limited-access road that was later widened to four lanes.[12] The final link in the 20-mile (32 km) section between Sheridan and Buffalo was opened in December 1968.[13]

The final Wyoming section of I-90 was opened to traffic on October 10, 1985, following four years of construction on 10 miles (16 km) between the Montana state border and Ranchester. It was also the final section of the Interstate Highway System to be completed in the state.[9] The Ranchester section, which had been completed for three months but delayed to coincide with work across the border in Montana, was dedicated by the governors of Montana and Wyoming in a joint ceremony.[14]

Exit list


I-90 west / US 87 north – Hardin
Continuation into Montana
US 14 west – Greybull, Lovell, Ranchester, Dayton, Yellowstone National Park, Grand Teton National Park
West end of US 14 overlap
14.6223.5314 WYO 345 – Acme
16.3426.3016 WYO 339 – Decker
I-90 BL east (Main Street)
23.1537.2623 WYO 336 (Fifth Street)

I-90 BL west / US 14 east (US 87 south) – Sheridan, Big Horn, Ucross
East end of US 14 / US 87 overlap
32.9853.0833Meade Creek Road – Big Horn
37.1659.8037Prairie Dog Creek Road
Johnson44.6971.9244Piney Creek Road (US 87 north)West end of US 87 overlap
47.7176.7847Shell Creek Road
51.3682.6651Lake De Smet
53.8386.6353Rock Creek Road

I-25 BL south / I-90 BL east – Buffalo
Eastbound exit and westbound entrance

I-25 south / US 87 south – Casper
East end of US 87 overlap; I-25 to 90 east exit 300; northern terminus of I-25
I-90 BL west / US 16 – Buffalo, Ucross
65.98106.1865Red Hills Road, Tipperary Road
69.64112.0769Dry Creek Road
73.01117.5073Crazy Woman Creek Road
77.91125.3877Schoonover Road
82.83133.3082Indian Creek Road
88.67142.7088Powder River Road
91.49147.2491Dead Horse Creek Road
Campbell102.52164.99102Barber Creek Road
106.14170.82106Kingsbury Road
113.97183.42113Wild Horse Creek Road
116.24187.07116Force Road

I-90 BL east / WYO 50 to US 14 west / US 16 west – Gillette
126.39203.40126 WYO 59 – Douglas

I-90 BL west / US 14 west / US 16 west – Gillette
West end of US 14/US 16 overlap
129.10207.77129Garner Lake Road
Wyodak132.99214.03132Wyodak Road

US 14 east / US 16 east – Moorcroft, Newcastle
East end of US 14/US 16 overlap

To US 14 / US 16 – Moorcroft
160.66258.56160Wind Creek Road
165.68266.64165Pine Ridge Road – Pine Haven
172.09276.95172Inyan Kara Road
178.92287.94178Coal Divide Road

I-90 BL east / US 14 to WYO 116 – Sundance
Sundance187.53301.80187 WYO 585 – Sundance, Newcastle

I-90 BL west / US 14 west – Sundance
West end of US 14 overlap
191.92308.87191Moskee Road
199.31320.76199 WYO 111 – Aladdin

I-90 east / US 14 east – Sturgis
Continuation into South Dakota
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

Business routes

Business routes are present in Sheridan (also carries US 14 Bus. and US 87 Bus.), Buffalo, Gillette, and Sundance (also part of US 14).


  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 17, 2022.
  2. ^ "WYDOT Travel Information Service (Cheyenne)". Wyoming Department of Transportation. Retrieved September 17, 2022.
  3. ^ a b c d Archived copy (PDF) (PDF). Wyoming Department of Transportation. October 2004. Archived from the original (PDF) on April 13, 2014. Retrieved January 30, 2014.{{cite map}}: CS1 maint: archived copy as title (link)
  4. ^ a b c d e f Google (October 31, 2010). "Interstate 90" (Map). Google Maps. Google. Retrieved October 31, 2010.
  5. ^ Leeright, Bob (May 4, 1960). "Clearmont Asks Injunction to Block Highway". Casper Tribune-Herald. Associated Press. p. 2. Retrieved November 13, 2022 – via
  6. ^ Bacon, Jack (January 4, 1957). "Angry Sheridan Group Protests Cheaper Route". Casper Morning Star. United Press International. p. 1. Retrieved November 13, 2022 – via
  7. ^ "Injunction to Halt Highway Work Denied". Casper Tribune-Herald. Associated Press. June 16, 1958. p. 1. Retrieved November 13, 2022 – via
  8. ^ a b "Supreme Court Denies Block to Interstate 90". Casper Tribune-Herald. Associated Press. December 6, 1960. p. 2. Retrieved November 13, 2022 – via
  9. ^ a b "Wyoming, Montana officials dedicate 10-mile section of I-90 near Sheridan". Casper Star-Tribune. Associated Press. October 10, 1985. p. B1. Retrieved November 13, 2022 – via
  10. ^ "Sheridan By-Pass Dedication Slated". Casper Tribune-Herald. Associated Press. July 27, 1962. p. 16. Retrieved November 13, 2022 – via
  11. ^ "Del Monte Says No Funds Wasted on Buffalo Road". Casper Tribune-Herald. Associated Press. October 15, 1962. p. 18. Retrieved November 13, 2022 – via
  12. ^ "Highway Opening Slated At Powder River Bridge". Casper Tribune-Herald. Associated Press. October 12, 1962. p. 3. Retrieved November 13, 2022 – via
  13. ^ "Open Interstate". Casper Star-Tribune. United Press International. December 3, 1968. p. 8. Retrieved November 13, 2022 – via
  14. ^ Thackeray, Lorna (October 10, 1985). "Governors plan Interstate 90 christening". The Billings Gazette. p. 2-B. Retrieved November 13, 2022 – via
  15. ^ "Reference Marker Book" (PDF). Wyoming Department of Transportation. November 2004. Archived from the original (PDF) on July 17, 2011. Retrieved October 31, 2010.

External links

Interstate 90
Previous state:
Wyoming Next state:
South Dakota