Interstate 25 in Wyoming

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Interstate 25

I-25 highlighted in red
Route information
Maintained by WYDOT
Length300.530 mi[1] (483.656 km)
NHSEntire route
Major junctions
South end I-25 / US 87 at the Colorado state line near Cheyenne
Major intersections
North end I-90 / US 87 near Buffalo
CountryUnited States
CountiesLaramie, Platte, Converse, Natrona, Johnson
Highway system
  • Wyoming State Highway System
WYO 24 US 26

Interstate 25 (I-25) is a part of the Interstate Highway System that runs from Las Cruces, New Mexico, to Buffalo, Wyoming. In Wyoming, the Interstate Highway runs 300.530 miles (483.656 km) from the Colorado state line near Cheyenne north to its national terminus at I-90 near Buffalo. I-25 connects Wyoming's largest city and capital, Cheyenne, with its second largest city, Casper, and the smaller communities of Wheatland, Douglas, and Buffalo. The highway also connects those cities with Denver and Billings via I-90. I-25 runs concurrently with U.S. Route 87 (US 87) for almost its entire course in Wyoming. The highway also has extensive concurrencies with US 20 and US 26 along its east–west segment through the North Platte River valley. The Interstate has business loops through Cheyenne, Chugwater, Wheatland, Douglas, Glenrock, Casper, and Buffalo.

Route description

Cheyenne to Wheatland

I-25 enters Laramie County concurrent with US 87 from Weld County, Colorado, southwest of Cheyenne and briefly runs parallel to a BNSF Railway line. The four-lane Interstate has its first interchange, a diamond interchange, with Wyoming Highway 223 (WYO 223, Terry Ranch Road), and crosses over the Union Pacific Railroad's Speer Subdivision rail line and over the BNSF rail line. I-25 meets High Plains Road at a dumbbell interchange, then has a diverging diamond interchange with WYO 212 (College Drive), a junction that serves as the southern end of Interstate 25 Business (I-25 Bus.). The freeway has a cloverleaf interchange with I-80, crosses over the Union Pacific's Laramie Subdivision and US 30 (Lincolnway), and has a four-ramp partial cloverleaf interchange with US 30, which here is also part of I-80 Bus.[1]

I-25 continues north along the western edge of the city of Cheyenne and along the eastern edge of Francis E. Warren Air Force Base, which is served by the next three interchanges. The highway has a five-ramp partial cloverleaf interchange with Missile Drive, crosses over a BNSF rail yard, and has a diamond interchange with Randall Road, which leads to Pershing Boulevard. I-25 reconnects with its business route at Central Avenue, where US 85 joins the Interstate. The freeway has a dumbbell interchange with Vandehei Street before leaving the city of Cheyenne and passing through the unincorporated area of Ranchettes. I-25 has an interchange with WYO 211 (Horse Creek Road) before US 85 splits to the northeast. There is no direct access from southbound I-25 to northbound US 85 at the latter interchange; southbound traffic uses the WYO 211 interchange to turn around to access northbound US 85.[1]

I-25 continues through sparsely populated northern Laramie County, where the Interstate crosses Lodgepole Creek and has five interchanges with minor roads: Ridley Road, an unnamed road only marked as exit 25, Whitaker Road, Nimmo Road, and an unnamed road that serves the Little Bear Community. The Interstate enters Platte County at its interchange with Bear Creek Road. I-25's first population center north of Cheyenne is Chugwater, where the highway crosses over a BNSF rail line and Chugwater Creek, has an interchange with WYO 211 and WYO 313 in town, and has an interchange with WYO 321 (Ty Basin Road) north of town. Those two interchanges serve as the termini for Chugwater's I-25 Bus. The Interstate meets the western end of WYO 314 (Slater Road) west of Slater; has minor interchanges with Hunton Road, Antelope Road, and Bordeaux Road; and meets the eastern end of WYO 34.[1]

Wheatland to Casper

I-25 bridge over the North Platte River at Douglas

I-25's next serves the town of Wheatland, the county seat of Platte County. Wheatland's I-25 Bus. splits off onto Mariposa Boulevard and provides access to WYO 310 and WYO 312. The Interstate and business route reconvene at the north end of town. I-25 has minor interchanges with Laramie River Road near its crossing of the Laramie River and with Johnson Road. The Interstate meets US 26 at a directional T interchange at Dwyer Junction, and the U.S. Route joins I-25 and US 87 heading north. I-25 has minor interchanges with El Rancho Road and an unnamed access road to Middle Bear around a junction with the southern end of WYO 319 (Cassa Road). The Interstate has an interchange with Wyoming Highway 319 Spur (WYO 319 Spur) in the town of Glendo, then parallels WYO 319 and the BNSF rail line northwest into Converse County to the west of the Glendo Reservoir, an impoundment of the North Platte River. I-25 crosses over the North Platte River and a BNSF rail line at Orin, where the Interstate has an interchange with and is joined by US 20; this interchange serves as the western terminus of US 18.[1]

I-25, US 87, US 20, and US 26 head west to Douglas, the county seat of Converse County. I-25 Bus. and its companion business routes—US 87 Bus., US 20 Bus., and US 26 Bus.—split northwest from a trumpet interchange into the city while I-25 and the mainline U.S. Routes pass to the south of the city. I-25 crosses over the BNSF rail line and the North Platte River, then curves northwest to meet the business routes at a trumpet interchange on the west side of the city near the business routes' intersection with WYO 59, which leads north to Gillette. I-25 continues west through interchanges with the western end of WYO 96 (La Prele Road), Inez Road, the road south to Ayres Natural Bridge, Barber Road, and Bixby Road. US 87, US 20, and US 26 diverge from I-25 east of Glenrock. I-25 Bus. joins the U.S. Routes in heading northwest toward the town, then reconnects with I-25 via WYO 95 (Deer Creek Road) south of town. I-25 enters Natrona County and has interchanges with WYO 253 (Hat Six Road) and WYO 258 (Wyoming Boulevard), which serves the town of Evansville to the north.[1]

Casper to Buffalo

I-25 south of Buffalo

I-25 briefly parallels US 87, US 20, and US 26 (Yellowstone Highway) and enters the city of Casper at a complex junction—the complexity is explained in the description for I-25 Bus.—where the Interstate crosses over Yellowstone Highway, the three U.S. Routes join I-25, I-25 Bus. splits from the Interstate to serve downtown Casper, and US 87 Bus., US 20 Bus., and US 26 Bus. split from the mainline U.S. Routes on Yellowstone Avenue. I-25, US 87, US 20, and US 26 cross over the BNSF rail line and are paralleled by a pair of frontage roads, F Street to the north and E Street to the south. There are several slip ramps between I-25 and the frontage roads serving the three streets that connect the portion of Casper north of the BNSF rail line to downtown Casper. The first street, which is Bryan Stock Trail north of the Interstate and Beverly Street to the south, is part of the complex junction between the mainline Interstate and U.S. Routes and their business routes. The second street is McKinley Street, and the third street is Center Street and carries the northmost portion of I-25 Bus. and US 87 Bus. E Street begins from an exit ramp to Center Street as I-25 and F Street cross the North Platte River. West of the river, the freeway has a diamond interchange with WYO 220 (Poplar Street), then curves north and has a diamond interchange with US 20 and US 26, which split west toward Shoshoni and Casper–Natrona County International Airport, and the access road to the Casper Events Center.[1]

I-25 leaves the city of Casper and has an interchange with WYO 254 (Wardwell Road) next to unincorporated Hartrandt and the town of Bar Nunn. The Interstate has an interchange with Ormsby Road in the Homa Hills area on the northern edge of the Casper populated area. I-25 has minor interchanges with Ranch Road and an unnamed road marketed as exit 223, then connects with the south end of WYO 387, which serves Midwest to the east, before entering Johnson County. The freeway has interchanges with Tisdale Mountain Road and Powder River Road just north of the highway's crossing of the South Fork of the Powder River. I-25 meets the southern end of WYO 196 (TTT Road) and parallels the state highway to Kaycee, where the highway crosses the Middle Fork of the Powder River and has an interchange with WYO 191. North of Kaycee, I-25 crosses the North Fork of the Powder River and has minor interchanges with Reno Road, Middle Fork Road, and Trabing Road and a crossings of two branches of Crazy Woman Creek near the Middle Fork interchange. The final I-25 Bus. and its companion, US 87 Bus., split off to the south of the town of Buffalo, the county seat of Johnson County. East of the town, I-25 has an interchange with US 16, which also carries I-90 Bus. The Interstate reaches its northern terminus at a directional T interchange with I-90. US 87 continues north along westbound I-90 toward Sheridan and Billings; I-90 also heads east toward Gillette. Buffalo's I-25 Bus. and US 87 Bus. have their northern terminuses at a partial interchange just west of the I-25/I-90 junction.[1]


The first section of I-25 to be built with funds from the Federal-Aid Highway Act of 1956 was a section near Cheyenne, which commenced in 1958.[2] Earlier funds from the state government had been used to begin work on a freeway bypass of Casper in 1953; its first 3-mile (4.8 km) section was opened to traffic on October 1, 1960.[3] The final section of the freeway, spanning 26 miles (42 km) between Casper and Kaycee, was opened on February 2, 1982.[4][5]

Exit list

I-25 south (US 87 south) – Ft. Collins, Denver
Continuation into Colorado
WYO 223 east (Terry Ranch Road)
4High Plains RoadDumbbell interchange

I-25 BL / US 87 Bus. north (College Drive) / WYO 212
Diverging diamond interchange
I-80 to US 85 – Laramie, Sidney
Split into exits 8B (west) and 8D (east); I-80 exits 359A-C
Cheyenne9.14014.7099 I-80 BL / US 30 (Lincolnway) – Central Business District
10.58617.03710DMissile Drive – Warren Gate 2Split into exits 10B (Warren Gate 2) and 10D (Missile Drive) southbound
11.23918.08711Randall Avenue, Pershing Boulevard – Warren Gate 1

I-25 BL / US 87 Bus. south (Central Avenue) / US 85
South end of concurrency with US 85
13.83422.26413Vandehei AvenueDumbbell interchange

WYO 211 (Horse Creek Road) to US 85 north – Torrington
US 85 north not signed northbound
US 85 north – Torrington
No southbound exit; north end of concurrency with US 85
21.31834.30821Ridley Road
25.45240.96125Exit 25
29.51247.49529Whitaker Road
34.44055.42634Nimmo Road
39.23563.14339Little Bear Community
county line
47.24876.03847Bear Creek Road
I-25 BL north (WYO 321 north) – Chugwater
57.64992.77757 I-25 BL / WYO 321 south (TY Basin Road) – Chugwater
WYO 314 east (Slater Road)
66.200106.53966Hunton Road
68.454110.16668Antelope Road
70.621113.65370Bordeaux Road
WYO 34 west – Laramie

I-25 BL / US 87 Bus. north – Wheatland

I-25 BL / US 87 Bus. south – Wheatland
84.744136.38284Laramie River Road
87.505140.82687Johnson Road
Dwyer Junction92.371148.65792
US 26 east – Guernsey, Torrington
Directional T interchange; south end of concurrency with US 26
94.825152.60694El Rancho Road
100.125161.136100Cassa Road (WYO 319)Southern terminus of WYO 319
104.043167.441104Middle Bear
Glendo111.675179.723111WYO 319 Spur – Glendo
US 18 / US 20 east – Lusk
South end of concurrency with US 20; western terminus of US 18
I-25 BL north – Douglas

I-25 BL south to WYO 59 – Douglas, Gillette
WYO 96 east (La Prele Road)
150.442242.113150Inez Road
151.166243.278151Ayres Natural Bridge
154.237248.220154Barber Road
156.178251.344156Bixby Road

I-25 BL / US 20 / US 26 west / US 87 north – East Glenrock
North end of concurrencies with US 20/US 26/US 87
I-25 BL east (WYO 95 north) – Glenrock, Rolling Hills
NatronaCasper182.530293.754182Hat Six Road (WYO 253) – Brookhurst
185.354298.298185 Wyoming Boulevard (WYO 258) – Evansville

US 20 / US 26 east / US 87 south / I-25 BL (N. Beverly Street) / Bryan Stock Trail
South end of concurrencies with US 20/US/26/US 87; eastern terminus of I-25 Bus.
187.527301.795187McKinley Street

I-25 BL / US 87 Bus. east / WYO 255 south (Center Street)
No northbound entrance; western terminus of I-25 Bus./US 87 Bus.; WYO 255 unsigned
188.600303.522188BPoplar Street (WYO 220)

US 20 / US 26 west to WYO 220 west – Shoshoni, Port of Entry
North end of concurrency with US 20/US 26
WYO 254 south (Wardwell Road)
Bar Nunn194312194Westwinds RoadOpened on October 5, 2018
Homa Hills197.522317.881197Ormsby Road
WYO 259 north (Horse Creek Ranch Road)
216.605348.592216Ranch Road
223.780360.139223Exit 223
WYO 387 north – Midwest, Edgerton
Johnson235.375378.799235Tisdale Mountain Road
246.560396.800246Powder River Road
WYO 196 north (TTT Road)
Kaycee254.254409.182254 WYO 191 – Kaycee
265.476427.242265Reno Road
280.177450.901280Middle Fork Road
291.077468.443291Trabing Road

I-25 BL / US 87 Bus. north
299.321481.710299 I-90 BL / US 16 – Buffalo
I-90 east – Rapid City
Northbound exit and southbound entrance; I-90 exit 56B

I-90 west / US 87 north – Sheridan
Northern terminus of I-25; north end of concurrency with US 87; I-90 exit 56B; tri-level directional T interchange.
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

Related routes

Interstate 25 Business


I-25 in Wyoming currently has no auxiliary Interstates but has six business loops and one business spur. Its business loops are located in Cheyenne, Chugwater, Wheatland, Douglas, Glenrock, and Casper. The business spur is located in Buffalo.


  1. ^ a b c d e f g h i "Vehicle Miles Book" (PDF). Wyoming Department of Transportation. 2013. Archived from the original (PDF) on 2015-05-21. Retrieved 2013-03-06.
  2. ^ "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
  3. ^ "Rites Saturday Mark Opening of F St. Highway". Casper Tribune-Herald. September 30, 1960. p. 2. Retrieved June 24, 2023 – via
  4. ^ "I-25 almost complete". Casper Star-Tribune. United Press International. February 2, 1982. p. B1. Retrieved November 13, 2022 – via
  5. ^ Waggener, John (June 21, 2021). "65 Years Ago: Ellis Armstrong and America's Interstate Highway System". American Heritage Center. Retrieved November 13, 2022.

External links

Interstate 25
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