STATE ROUTE DESCRIPTION COUNTY MILEAGE NAMING
Routing: Wyoming 310 travels from Business Loop I-25 and U.S. 87 at Wheatland west to the Wheatland Number 1 Reservoir.
Mileposts: Mileposts increase from east to west. Milepost 0.00 is Business Loop I-25 and Business U.S. 87 (MP 79.40) and Wyoming 312 (MP 7.30). There is a milepost equation at 0.56BK=0.50AH, and Wyoming 310 passes under Interstate 25 at Milepost 0.63, the Oak Street Underpass. The west city limits of Wheatland are at Milepost 1.00, and Wyoming 310 intersects Wyoming 311 at Milepost 4.50. The route ends at Milepost 8.49, at the junction with the county road to the reservoir.
Platte 8.55 Oak Street
Routing: Wyoming 311 travels from Wyoming 310 north to Platte County Road 139 and County Road 90 (Fletcher Park Road) just north of its junction with Wyoming 310.
Mileposts: Mileposts increase from south to north, from 0.00 to 1.99.
Platte 1.99
Routing: Wyoming 312 travels from Wyoming 34 north to Business Loop I-25 and Business U.S. 87 in Wheatland.
Mileposts: Mileposts increase from south to north. Milepost 0.00 is Wyoming 34, and Milepost 6.23 marks the western city limits of Wheatland. The route passes by Interstate 25 at Milepost 7.18 and ends at Milepost 7.30, which is the junction with Business Loop I-25 and Business U.S. 87 (MP 79.40) and Wyoming 319 (MP 0.00).
History: Wyoming 312 is the original path that Wyoming 34 used to take into Wheatland before it was realigned to go directly to the interstate rather than into Wheatland.
Platte 1.99 South Street and Preuit Road
Routing: Wyoming 313 travels from Business Loop I-25 and Business U.S. 87 in Chugwater east to U.S. 85 near Hawk Springs State Recreation Area. The 1997 Wyoming Reference Marker Guide indicated that the southern half of today’s Business Loop I-25 in Chugwater was originally part of Wyoming 313. This initial segment of Wyoming 313 followed old U.S. 87 from Interstate 25 to the Chugwater town center, then turned east to meet U.S. 85.
Mileposts: Mileposts increase from west to east. The route begins at Milepost 54.59, which is the junction with Interstate 25 and U.S. 87 (MP 54.59) and Wyoming 211 (MP 63.95) in Chugwater. Wyoming 313 leaves Chugwater at Milepost 54.84, and there is a milepost equation (55.18BK=100.00AH) where it meets Wyoming 321 (MP 55.18). From here, the route leaves Chugwater at Milepost 100.74, and it crosses Goshen-Platte County Line at Milepost 109.31. There is another realignment at 116.83BK=116.81AH, and the route ends at Milepost 130.20 at U.S. 85.
Platte, Goshen 34.05
Routing: Wyoming 314 travels from Interstate 25 east to Buckskin Road near the state line, just east of the Wyoming 315 junction and Slater.
Mileposts: Mileposts increase from west to east. Milepost 0.00 is at Interstate 25 and U.S. 87 (MP 65.25) and Milepost 6.56 is at Wyoming 315 North (MP 0.00). The route ends at Milepost 8.57.
Platte 8.57 Slater Road
Routing: Wyoming 315 travels from Wyoming 314 north to an intersection with Platte County Road 232 (Bordeaux Road).
Mileposts: Mileposts increase from south to north. Milepost 0.00 is Wyoming 314 (MP 6.56), and Milepost 3.01 is the end of Wyoming 315.
Platte 3.01 Pioneer Road
Routing: Wyoming 316 travels from Business Loop I-25 and Business U.S. 87 at Wheatland east to Dickinson Hill Road and Deer Creek Road junction.
Mileposts: Wyoming 316’s mileposts increase from west to east. The route begins at Milepost 0.00 at Business Loop I-25 and Business U.S. 87 (P-57, MP 80.10). At Milepost 0.13 is a Railroad At-Grade Crossing, and the route leaves Wheatland at Milepost 0.82. At Milepost 7.86, the route changes its Wyoming State Control Number (End S-1604/Begin SH-316), and Wyoming 316 ends at Milepost 11.91.
Platte 11.91
History: Wyoming 316 was signed sometime between 1926 and 1933 to run from Midwest to Gillette via modern-day Wyoming 387 and Wyoming 59. It was recommissioned in 1940 as part of Wyoming 116. There is a possibility that Wyoming 316 remained as the designation for modern-day Wyoming 50, but there is no map that shows this designation. Converse; Campbell N/A Highway 387; Highway 59
Routing: Wyoming 317 travels from U.S. 26 north to the southern entrance of Guernsey State Park. The highway continues into the state park as Lake Shore Drive, leading to Guernsey Dam and Guernsey Reservoir.
Mileposts: Wyoming 317’s mileposts increase from south to north. Milepost 0.00 is U.S. 26 (P-27, MP 14.42), and Wyoming 317 ends at Milepost 1.65 at the 1927 Guernsey Dam.
Platte 1.65 Lake Shore Drive
Routing: Wyoming 318 travels from Wyoming 270 at Hartville east to the old mining town of Sunrise.
Mileposts: Mileposts increase from west to east. The route begins at Milepost 4.53 at Wyoming 270, and it enters Hartville at Milepost 5.18. The route ends at Sunrise at Milepost 5.62. Wyoming 318 used to begin as U.S. 26 near Guernsey and end at Sunrise, with a 90 degree turn at Hartville. The stretch between Guernsey and Hartville was recommissioned as Wyoming 270 for continuity purposes during the 1970s when that road was completed between Manville and Hartville.
Platte 1.09
Routing: Wyoming 317 travels from Interstate 25 and U.S. 87 Exit 100 north to U.S. 18-20 at Orin.
Mileposts: Wyoming 319’s mileposts increase from south to north. Wyoming 319 begins at Milepost 100.13 at Interstate 25 and U.S. 87 (MP 100.15) Cassa Interchange. The route enters Glendo from the south at Milepost 114.28, then has a milepost equation at Milepost 114.62BK=211.88AH, which is the junction with Wyoming 319 Spur (Milepost 111.88) West (Glendo Connector). Wyoming 319 exits Glendo at Milepost 212.41, then crosses the Converse-Platte County Line at Milepost 221.00. The route crosses the North Platte River at Milepost 225.31, and ends at Milepost 226.43, its junction with U.S. 18-20 (P-40, MP 1.84). Wyoming 319 is the original U.S. 87 and old U.S. 185.
Platte, Converse 28.84 Old Yellowstone Highway
Routing: Spur Wyoming 319 is 0.20 mile in length and travels from Wyoming 319 (MP 211.88AH) west to Interstate 25 and U.S. 87 (MP 111.68) at the Glendo Interchange. Platte 0.20 Glendo Spur
Routing: Wyoming 320 travels from Business Loop I-25 and Business U.S. 87 in Wheatland north to U.S. 26.
Mileposts: Mileposts increase from south to north. Milepost 0.00 is Business Loop I-25 and Business U.S. 87 (P-57, MP 81.03). The route crosses the corporate limits of Wheatland at Milepost 0.06, and passes over the Laramie River at Milepost 3.92 and the North Laramie River at Milepost 5.04. Wyoming 320 ends at Milepost 12.33 at its junction with U.S. 26 (P-27, MP 2.60).
History: The highway that now carries Wyoming 320 was originally part of U.S. 87 (185).
Guide: Located near Wheatland is the massive Laramie River Power Station, built in phases between 1976 and 1982. This coal-fired facility is a 1,650-megawatt, electric generating facility — part of the Missouri Basin Power Project (MBPP). According to a web page related to the Laramie River Station, the power station cost $1.6 billion to build, and it is one of the largest consumer-owned, power supply projects in the United States. Overall, the project provides electric power to more than 100 rural electric cooperatives and nearly 80 municipal electric systems serving more than 2 million people in Colorado, the Dakotas, Iowa, Minnesota, Montana, Nebraska and Wyoming. The nearby Grayrocks Dam and Reservoir, which is located on the Laramie River about seven miles east of the station, is the principal water supply for the power plant. The water is used for steam and evaporative cooling of the plant. The reservoir is also used for recreation, with boat ramps and other facilities available. Finally, the Tri-State and Basin Electric company constructed and operate an extensive transmission line network as part of the project. According to the web page, this includes 536 miles of 345-kilovolt line, 133 miles of 230-kilovolt line and ancillary substations and switching facilities. This transmission network extends into Colorado, Nebraska and Wyoming and ties Laramie River Station into other existing power grids.
Platte 12.33 Old Yellowstone Highway
History: Wyoming 320 was designated along what is now Wyoming 789 between Lander and Shoshoni between 1939 and 1950. It was originally U.S. 320 between 1926 and 1938. In 1939, U.S. 320 between Riverton and Shoshoni was recommissioned as Wyoming 320. In 1940, when U.S. 287 and Wyoming 287 were rerouted, Wyoming 320 was extended southwest to Lander. Wyoming 320 maintained this Lander to Shoshoni routing until 1950, when U.S. 26 was commissioned. Wyoming 320 persisted until 1954, when Wyoming 789 was commissioned. Fremont N/A Wyoming 789

Routing: Wyoming 321 travels from Wyoming 313 north to Interstate 25 and U.S. 87 at Exit 57 via Chugwater.
Mileposts: The route begins at Milepost 55.18 Wyoming 313 (MP 100.00). Wyoming 321 passes through the Chugwater corporate limits at Milepost 56.64, then has a realignment at Milepost 57.78BK=57.84AH. The route ends at Milepost 57.93, which marks the interchange with Interstate 25 and U.S. 87 (MP 57.65) – Ty Basin Interchange. Wyoming 321 was originally U.S. 87 (185).
Platte 2.75 Old Yellowstone Highway
History: Wyoming 322 is a former designation for what is now Wyoming 211 in Platte County (west of Interstate 25 and Business Loop I-25 southern interchange in Chugwater). Platte N/A Wyoming 211
Routing: Wyoming 330 travels from Business Loop I-90 and Business U.S. 14-87 (Coffeen Avenue) at Sheridan west to Sheridan Golf Course. West of the golf course, the roadway shifts to local maintenance as part of Sheridan County Road 74 (Soldier Creek Road). At the other end of the route, Wyoming 330 changes into Wyoming 336 as it crosses Business Loop I-90 and Business U.S. 14-87 (Coffeen Avenue).
Mileposts: Wyoming 330’s mileposts increase from east to west. Milepost 0.00 is Business Loop I-90 and Business U.S. 14-87 (P-60, MP 22.61) and Wyoming 336 East (S-1704, MP 0.00). The city limits are at Milepost 1.11, and the route ends at Milepost 3.07 at the junction with Sheridan County Road 74.
Sheridan 3.30 Fifth Street
History Wyoming 330 was the number assigned to the route now called Wyoming 789 between Creston Junction and Baggs before the multi-state route 789 was implemented (and subsequently retracted). That route was Wyoming 87 before it was Wyoming 330. This route which may have been intended to be a future extension of the original U.S. 87 in 1930, and it was proposed in the 1950s to be a southerly extension of U.S. 187. Sweetwater, Carbon DEAD Baggs Road/Wyoming 789
Routing: Wyoming 331 travels from Business Loop I-90 and U.S. 14-87 at Sheridan west to Sheridan County Road 53 in Beckton. Changes into Sheridan County Road 53 (Big Goose Canyon Road).
Mileposts: Mileposts increase from east to west. Milepost 0.00 is Business Loop I-90 and Business U.S. 14-87 (P-60, MP 23.34). At Milepost 0.86, Wyoming 331 leaves Sheridan, and the route ends at Milepost 9.92 at Beckton where it meets Sheridan County Road 53.
Sheridan 9.92 Loucks Street; Big Goose Canyon Road
Routing: Wyoming 332 travels from Business Loop I-90 and U.S. 14-87 in Sheridan south to the Wyoming Girls School.
Mileposts: Mileposts increase from north to south. Milepost 0.00 is Business Loop I-90, Business U.S. 14-87 (P-60, MP 23.46). Wyoming 332 leaves Sheridan at Milepost 0.56, then meets Wyoming 333 at Milepost 1.35. Milepost 1.62 is Wyoming 334 (MP 0.00), and the route ends at Milepost 5.44 at its junction with U.S. 87 (S-1708, MP 23.34).
Sheridan 5.44 Big Horn Avenue
Routing: Wyoming 333 travels from Wyoming 332 west into the Sheridan County Airport.
Mileposts:Mileposts increase from east to west as the route enters the airport. Milepost 0.00 is Wyoming 332 (MP 1.35), and Milepost 0.75 is the Sheridan County Airport.
Sheridan 5.44 Airport Road
Routing: Wyoming 334 travels from Business Loop I-90 and Business U.S. 14-87 west to Wyoming 332 near the Sheridan County Airport. West of Wyoming 332 (Big Horn Avenue), Wyoming 334 continues as Sheridan County Road 34 to connect to Wyoming 333 (Airport Road).
Mileposts: Mileposts increase from west to east. Milepost 0.00 is Wyoming 332 (MP 1.62). The route ends at Milepost 0.74 at Business Loop I-90; U.S. 87 South; Business U.S. 14-87 (P-60, MP 25.16).
Sheridan 0.74
Routing: Wyoming 335 travels from U.S. 87 south of Sheridan south to Big Horn and the Bradford Brinton Memorial Ranch. At that point, Wyoming 335 changes into Sheridan County Road 26 (Grade Road) as it approaches the Bighorn National Forest.
Mileposts: Mileposts increase from northeast to southwest. Milepost 0.00 is U.S. 87 (MP 29.11). Milepost 3.14 is Big Horn, and Milepost 7.20 is Colorado Colony Ditch. Wyoming 335 ends at Milepost 9.71.
Sheridan 9.71 Brinton Road; Red Grade Road
Routing: Wyoming 336 travels from Business Loop I-90 and Business U.S. 14-87 at Sheridan east to Wyarno. Beyond Wyarno, the highway changes into Sheridan County Road 42, Ulm Road. Fifth Street changes to Wyoming 330 west of Business Loop I-90.
Mileposts: Mileposts increase from west to east. Milepost 0.00 is Business Loop I-90 and Business U.S. 14-87 (P-60, MP 22.61) and Wyoming 330 West (MP 0.00). An at-grade railroad crossing is at Milepost 0.14, and the route leaves the corporate limits of Sheridan at Milepost 0.63. The route intersects Interstate 90 and U.S. 14-87 (MP 23.15) and Milepost 0.95. At Milepost 1.18 is the Sheridan Information Center and Rest Area. Two more railroad at-grade crossings are at Mileposts 7.04 and 7.25. Wyarno is at Milepost 10.21, and the route ends at Milepost 11.52.
Sheridan 11.52 Fifth Street; Ulm Road

Routing: Wyoming 337 travels from Business Loop I-90 and Business U.S. 14-87 in Sheridan west to Fort MacKenzie Reservation and Veterans Hospital.
Mileposts: Mileposts increase from east to west. Milepost 0.00 is Business Loop I-90 and Business U.S. 14-87 (P-60, MP 21.66), and the route enters Fort MacKenzie at Milepost 0.88. The route ends at Milepost 1.54 at Fort MacKenzie Road.

Sheridan 1.54 Fort Road

Routing: Wyoming 338 travels from Business Loop I-90 and U.S. 14-87 at Sheridan near Interstate 90 Exit 20 north to the Montana State Line.
Mileposts: Mileposts increase from south to north. Milepost 0.00 is Business Loop I-90 and Business U.S. 14-87 (P-60, MP 21.14). The Sheridan Port of Entry is at Milepost 0.12, and the route passes under Interstate 90 at Milepost 0.60. The northern urban limits of Sheridan are at Milepost 1.71, and the Burlington Northern Railroad Separation is at Milepost 3.29. Milepost 4.15 is Wyoming 339 West (Jensik Connector, MP 0.00). Wyoming 338 crosses over the Tongue River at Milepost 10.73 and enters the state of Montana at Milepost 15.03.
History: Wyoming 338 between Business Loop I-90 and Wyoming 339 is the original U.S. 14-87 route prior to the construction of Interstate 90.

Sheridan 15.03 Decker Road; Higby Road
Routing: Wyoming 339 links Wyoming 338 and I-90 four miles north of the north Sheridan business loop exit just south of Acme.
Mileposts: Mileposts increase from east to west. Milepost 0.00 is Wyoming 338 (MP 4.15), Milepost 0.02 is a Burlington Northern Railroad At-Grade Crossing, and Milepost 1.01 is Interstate 90 and U.S. 14-87 (MP 16.34) at the Dietz Interchange.
History: Wyoming 339 between Wyoming 338 and Interstate 90 (U.S. 14-87) is the original U.S. 14-87 route prior to the construction of Interstate 90.
Sheridan 1.01 Jensick Connector
Routing: Wyoming 340 travels from Wyoming 194 at Story west to the Fish Hatchery on North Piney Creek.
Mileposts: Mileposts increase from east to west, from 0.00 at Wyoming 194 to 1.36 at its end.
Sheridan 1.36
Routing: Wyoming 341 travels from U.S. 14-16 south to Sheridan County Road 38 (Wild Horse Road) at Arvada. At Arvada, Wyoming 341 changes into Sheridan County Road 273 (Upper Powder Road).
Mileposts: Mileposts increase form north to south. Milepost 0.00 is U.S. 14-16 (S-302, MP 54.82), and an at-grade railroad crossing is at Milepost 1.85. The route ends at Milepost 3.19 in Arvada.
Sheridan 1.36 Arvada Spur
Routing: Wyoming 342 travels from U.S. 87 and Interstate 90 just north of Banner.
Mileposts: Wyoming 342’s mileposts increase from east to west. Milepost 0.00 is Interstate 90 (MP 33.60). The route ends at Milepost 1.14, which is the junction with U.S. 87 (S-1708, MP 33.93).
Sheridan 1.14 Meade Road
Routing: Wyoming 343 travels from U.S. 14 at Dayton north to Wyoming 345 near Parkman.
Mileposts: Wyoming 343’s mileposts increase from north to south. Milepost 0.00 is Wyoming 345 (MP 5.80), and a railroad at-grade crossing is adjacent to this intersection at Milepost 0.02. Wyoming 343 ends at its junction with U.S. 14 (P-35, MP 83.64) at Milepost 5.24. Wyoming 330 through 345 are all clustered in Sheridan County.
Sheridan 5.24
Routing: Wyoming 344 travels from U.S. 87 and Wyoming 193 at Banner south to a landslide that has permanently closed U.S. 87 near Story and Banner. Traffic has had to take Wyoming Highway 193 as an alternate route.
Mileposts: Mileposts increase from north to south. Milepost 38.90 is the state of the route at Wyoming 193 (MP 106.19). There is one milepost equation at 42.49AH=42.46BK, which marks the Johnson-Sheridan County Line. The route ends at Milepost 43.82 where it intersects Wyoming 193 (MP 100.00AH).
Sheridan 4.95 U.S. 87
Routing: Wyoming 345 travels from the Montana State Line south to U.S. 14 at Ranchester, then east to meet Interstate 90 (Exit 14) and the town of Acme.
Mileposts: Mileposts increase from northwest to southeast. Milepost 0.00 is the Montana State Line, and it meets Wyoming 343 southbound at Milepost 5.80. The northern corporate limits of Ranchester are at Milepost 12.26. Wyoming 345 and U.S. 14 overlap between Mileposts 12.80 and 12.85. At Milepost 12.89, Wyoming 345 leaves Ranchester, and it meets Interstate 90 and U.S. 14-87 (MP 14.62) at Milepost 19.27 (this is the Acme Interchange). Wyoming 345 passes over the Tongue River at Milepost 20.23, and the route ends at Milepost 21.14 at its junction with Acme Access Road.
History: Wyoming 345 between the Montana State Line and Interstate 90 was originally U.S. 87. This section of U.S. 87 was the last to be decommissioned in favor of the interstate; in March 1985, when Interstate 90 was completed, the Interstate Highway System in Wyoming was completed. At the same time, U.S. 87 was rerouted to Interstate 90, and U.S. 87 north of Ranchester became Wyoming 345.
Sheridan 21.14
Routing: Wyoming 346 travels from U.S. 87 and Wyoming 193 near Story north to a landslide that has permanently closed U.S. 87 near Story and Banner. Traffic has had to take Wyoming Highway 193 as an alternate route.
Mileposts: Mileposts for Wyoming 346 and Wyoming 344 increase from north to south. Milepost 38.90 is the state of the route at Wyoming 193 (MP 106.19). There is one milepost equation at 42.49AH=42.46BK, which marks the Johnson-Sheridan County Line. The route ends at Milepost 43.82 where it intersects Wyoming 193 (MP 100.00AH).
Sheridan 4.95 U.S. 87
Routing: Wyoming 350 travels from U.S. 189 in Big Piney west toward the Bridger-Teton National Forest along South Piney Creek.
Mileposts: Mileposts increase from east to west. Milepost 0.00 is U.S. 189 (P-11, MP 109.38), and the route passes through the western corporate limits of Big Piney at Milepost 1.39. The route ends at Milepost 5.06.
Sublette 5.06 Middle Piney Road
Routing: Wyoming 351 travels from U.S. 189 at Marbleton east to U.S. 191 approximately 23 miles south of Pinedale.
Mileposts: Mileposts increase from west to east. Milepost 0.00 is U.S. 189 (P-11, MP 109.38). Wyoming 351 crosses the Green River at Milepost 7.30 and the New Fork River at Milepost 12.89. The route ends at Milepost 24.18 at U.S. 191 (P-13, MP 76.75).
Sublette 24.18
Routing: Wyoming 352 travels from U.S. 191 in Pinedale north to the Green River Lakes via Cora. The state highway changes into Forest Service Road 10091.
Mileposts: Mileposts increase from south to north. Milepost 0.00 is U.S. 191 (P-13, MP 105.54). Wyoming 352 enters Cora at Milepost 4.18, then crosses the Bridger National Forest Boundary at Mileposts 22.21, 23.68, and 25.31. The route ends at the re-entry into the forest at Milepost 25.31.
Sublette 25.31
Routing: Wyoming 353 travels from U.S. 191 at Boulder southeast to Big Sandy.
Mileposts: Mileposts increase from northwest to southeast. Milepost 0.00 is U.S. 191 (P-13, MP 87.80). Milepost 14.40 marks the East Fork River crossing, and the route ends at Milepost 15.51.
Sublette 15.51
Routing: Wyoming 354 travels from U.S. 189-191 at Daniel Junction west to Merna via Old Fort Bonneville.
Mileposts: Mileposts increase from east to west. The route begins at Milepost 0.01 at U.S. 189-191 (P-13, MP 110.75) in Daniel Junction. It crosses the Green River at Milepost 1.26, and it ends at Milepost 6.18.
Sublette 6.17 Daniel-Merna Road
Routing: Wyoming 370 travels from Interstate 80 and U.S. 30 Exit 111 southeast to Wyoming 430 via Middle Baxter Road.
Guide: The interchange with Wyoming 370 is signed alternately as “Airport Road” and “Baxter Road.” There are no Wyoming 370 shields placed on these guide signs.
Sweetwater 4.63 Baxter Road
Routing: Spur Wyoming 370 travels from the Wyoming 370 mainline to the Rock Springs Regional Airport; this route is slated to be transitioned to Sweetwater County control.
Mileposts: Mileposts increase from north to south. Milepost 0.00 is Interstate 80 and U.S. 30 (MP 111.16). There is a Union Pacific Railroad Separation at Milepost 0.66 and a milepost equation for realignment at 1.34BK=1.37AH. The airport is at Milepost 4.66.
Guide: The airport sits on top of a large bluff, and Wyoming 370 travels in wide arcs up to the top of the hill. The location of the airport on a bluff makes this one of the most interesting airport approaches by airplane.
Sweetwater 4.63 Airport Road
Routing: Wyoming 371 travels from Interstate 80 and U.S. 30 at Exit 122 north to Superior.
Mileposts: Mileposts increase from south to north. Milepost 0.00 is at Interstate 80 and U.S. 30 (MP 122.27). The route passes through the town of Superior between Mileposts 6.78 and 7.16. Wyoming 371 ends at Milepost 7.30.
History: Superior is an old coal mining town that used to have more people than Rock Springs, but today is much smaller. This town’s rise and fall through the years is indicative of the boom and bust cycle of many Wyoming towns dependent on mineral wealth.
Sweetwater 7.30 Superior Road
Routing: Wyoming 372 travels from U.S. 189 just south of the Fontenelle Reservoir southeast to the Interstate 80, U.S. 30, and Wyoming 374 junction just west of Jamestown (Exit 83). In 1994, this road was reconstructed and widened to accommodate additional traffic due to the various mining and oil exploration operations north of Green River. Sweetwater; Lincoln 19.00 La Barge Road
History: Wyoming 373 used to travel from the Utah-Wyoming State Line north to Interstate 80 and U.S. 30 between Green River and Rock Springs. This state route was decommissioned in 1982 in favor of the extension of U.S. 191. Prior to 1982, when U.S. 191 was U.S. 187, the portion of U.S. 191 south of Interstate 80 (Flaming Gorge Road, from Interstate 80 and U.S. 30 Exit 99 south to the Utah-Wyoming Border) was Wyoming 373. At the state line, the road continued as Utah 260 south to Dutch John. When U.S. 191 was realigned in 1982, both of these routes were deleted. Wyoming 373 may have been planned as part of the proposed but never adopted northern extension of U.S. 163 along the path of current U.S. 191. Sweetwater N/A East Flaming Gorge Road; U.S. 191

Routing: Wyoming 374 is broken into two segments: (1) The western segment is the Interstate 80 frontage road from Cedar Mountain Road (at Interstate 80 Exit 61) east to U.S. 30 near Granger. (2) The eastern segment extends from Interstate 80 and U.S. 30 Exit 68 at Little America east to Business Loop I-80 and Business U.S. 30 (Flaming Gorge Way) in Green River.

Mileposts: Mileposts increase from west to east. Wyoming 374 begins at Milepost 61.59 at its junction with Interstate 80 (MP 61.59) and has its route break at Milepost 66.39 at U.S. 30 (MP 99.54). The route resumes at Milepost 69.49 at Interstate 80 and U.S. 30 (MP 68.97) in Little America. There is a Union Pacific Railroad Separation at Milepost 77.30 and Milepost 82.67. The Black’s Fork River is at Milepost 78.13, and Wyoming 374 meets Wyoming 374 (La Barge Road) at Milepost 83.56. Wyoming 374 crosses and intersects Interstate 80 and U.S. 30 (MP 83.01) at Milepost 83.67. The route crosses the Green River to enter Jamestown at Milepost 87.17, and it enters the city of Green River at Milepost 90.03. Wyoming 374 ends at Milepost 90.14 at its junction with Business Loop I-80 and U.S. 30 (To Wyoming 530) (P-52, MP 89.69).

History: Wyoming 374 is the original U.S. 30. The original route of U.S. 30 is mostly frontage for Interstate 80, but the parts that are designated are: Business Loop I-80 through Bridger Valley, Wyoming 374 from near Granger to Green River, Wyoming 76 between Rawlins and Sinclair, Wyoming 225 (Otto Road) west of Cheyenne, and the various business loops through the cities.

Guide: The Interstate 80 frontage road (Wyoming 374) provides primary access to Jamestown, a western suburb of Green River that sits alongside a hill above the river. At the floor of the valley (alongside the river) is a nine-hole golf course — the Rolling Green Golf Course. Wyoming 374 also accesses the five trona mines that line Interstate 80 between Exits 68 and 83: Solvay Minerals, FMC, OCI, General Chemical, and Texas Gulf (as of 1995, but these have likely changed). Church and Dwight and Arm and Hammer have operations here too. As a result, Wyoming 374 is heavily traveled by trucks and other such vehicles. In early 1997, the five trona mines were operated by Rhone Poulenc, FMC, General Chemical, Solvay, and Texas Gulf. Some of these operators have changed since then. Wyoming 374 is not signed at any of its interactions with Interstate 80. During the Summer of 1997, Exit 89 (West Green River Business Loop Interchange) was closed due to bridge reconstruction and realignment. During that time, locals used the Wyoming 372 and 374 Exit 83 to get into town, while through travelers followed the construction signs that instructed travelers to take the East Green River Business Loop Interchange (Exit 91).

Sweetwater 25.34 Jamestown Road
Routing: Wyoming 385 is a 0.95-mile spur from U.S. 30 just north of the Interstate 80 and Wyoming 374 junction west into Granger. Sweetwater 0.95 Granger Road

Routing: Wyoming 376 travels from Business Loop I-80 and Business U.S. 30 (Dewar Drive) southeast to Wyoming 430 then northeast back to Business Loop I-80 and Business U.S. 30 (Pilot Butte Avenue).
Mileposts: Mileposts increase from west to east. Milepost 0.00 is the western terminus at Business Loop I-80 and Business U.S. 30 (P-53, MP 103.59), which is locally known as Dewar Drive. At Milepost 0.26 is a Union Pacific Railroad Separation. Milepost 2.35 is Wyoming 430 South (MP 0.00), and Milepost 2.52 is the Hampshire Street Overpass. Two more Union Pacific Railroad separations are at Mileposts 2.60 and 4.09. The route ends at Milepost 4.31 where Wyoming 376 rejoins Business Loop I-80 and Business U.S. 30, now known as Pilot Butte Avenue (P-53, MP 106.09) on the eastern side of town.

History: Wyoming 376 used to continue in a counterclockwise direction from its current end to connect back to Former U.S. 187 (Elk Street), but this section is no longer under state jurisdiction. Since U.S. 191 was routed onto the Interstate north of Rock Springs, this portion of Elk Street is designated as Spur U.S. 191 (yet is not signed as such).
Guide: Southwestern Wyoming towns rely on mining for their welfare: coal in Rock Springs and trona in Green River. While the trona mines near Green River are younger, the coal mines in Rock Springs have been around for generations. As a result of years of mining activity, Rock Springs has many miles of coal tunnels underneath the town. Some of these abandoned tunnels have filled with groundwater and have even begun to collapse, causing parts of the city to suffer sinkholes and partial collapse in some areas.

Sweetwater 4.31 Circumferential Highway (Rock Springs Beltway)
Routing: Wyoming 377 travels from Interstate 80 and U.S. 30 Exit #130 at Point of Rocks northeast to the Jim Bridger Power Plant. Mileposts increase from southwest to northeast.
Mileposts: Milepost 0.00 is Interstate 80 and U.S. 30 (MP 130.84) and Milepost 1.96 is end Wyoming 377 at the Jim Bridger Power Plant.
Guide: Wyoming 377 is primarily used to commute to and from the Jim Bridger Power Plant, one of the largest coal-fired power plants in Wyoming. This power plant connects to several high-voltage transmission lines that carry electricity west into Idaho.
History: At its southern end, where Wyoming 377 parallels Interstate 80, the route was once part of the original U.S. 30.
Sweetwater 1.96 Point of Rocks Road
Routing: Wyoming 387 travels from Interstate 25 and U.S. 87 at Exit 227 northeast to Wyoming 59 at Reno Junction via Midwest and Wright.
History: In 1936, Wyoming 387 was commissioned to replace Wyoming 185 between Douglas and Gillette. Wyoming 387 was rerouted in 1945, when Wyoming 316 route. A Rand McNally map shows that this portion of Wyoming 59 may have been called Wyoming 87 in 1947, but the official Wyoming state highway maps show this as Wyoming 59 in that year. Back to Wyoming 387: It was recommissioned in the 1940s to run from U.S. 87 in Midwest to Wyoming 59 in Reno Junction. Wyoming 387 maintained this route until the 1980s, when I-25 was completed. At that time, Wyoming 387 was extended west along old U.S. 87 to meet the new I-25. Old U.S. 87 south of Midwest became Wyoming 259.
Natrona, Johnson, Campbell 57.81
Routing: Wyoming 390 travels from Wyoming 22 (S-2000, MP 4.06) at Wilson north to the Grand Teton National Park boundary via Teton Village. Motorists may continue north into the national park, connecting with the park road system near Moose. A portion of this park road is unpaved but usually passable in a passenger car.
Mileposts: The mileposts increase from south to north. Milepost 0.00 is the junction with Wyoming 22. Two realignments are at 0.15BK=0.14AH and 0.38BK=0.40AH. Wyoming 390 ends at Milepost 7.71 at the Grand Teton National Park boundary.
Teton 7.70 Moose-Wilson Road
Routing: Wyoming 391 travels from U.S. 26-89-189-191 (P-10, MP 145.25) 18 miles north of Hoback Junction west to the Jackson Area Wyoming DOT Maintenance Shop.
Mileposts: Wyoming 391’s mileposts increase from east to west. Milepost 0.00 is U.S. 26-89-189-191 and Milepost 0.30 is the entrance to the Jackson Wyoming DOT Department Shop. This is another very short Wyoming state route.
Teton 0.30 Jackson Area Wyoming DOT Maintenance Shop

Page Updated June 10, 2012.