Wyoming’s highway system is rooted in the days of the Old West. Pioneer trails between the East and West Coasts crisscrossed Wyoming. Several of these, such as the Oregon, Overland, and Mormon Trails, were the main routes across the Northern Rocky Mountains to destinations such as California and Oregon.

With the development of the automobile, Wyoming’s landscape changed dramatically. The old “Pony Express” days were over; the stagecoach gave way to the “metal horse.” Gasoline and oil became permanent fixtures, and long dirt stretches slowly evolved into long asphalt and concrete stretches.

This page discusses the early development of Wyoming highways, beginning with the named highways of the 1910s and 1920s and continuing on to the first numbered highways in the state. These numbered highways gave way to the first incarnation of the U.S. Highway System. Later incarnations came with the Great Recommissioning of 1936 and the Interstate Highway Act of 1956.

The Named Highways of the 1910s and 1920s

In the early part of this century, travel through Wyoming was via trail along named rather than numbered highways. The “highways” of this era were not paved, but were usually well-traveled paths leading from one town to the next, frequently following rail lines and rivers. Wyoming was no exception.

Named highways were first promoted in Wyoming by the Wyoming Highways Association, a group of volunteers dedicated to promoting new highway corridors through the state. This organization, formed in 1912, helped bring the Lincoln Memorial Highway Association into the state in 1913. By 1914, several other named highways (such as the Black and Yellow Trail, the Yellowstone Highway, and others) were developed along principal trading routes. These routes eventually developed into modern transportation corridors.

The following list describes several of the more popular named highways that used to run through Wyoming.

Trail Name Approximate U.S. Highway Routing in Wyoming Notes
Abraham Lincoln Memorial Highway U.S. 30 This was perhaps the most famous named highway to serve Wyoming.
Black and Yellow Trail U.S. 16 Starting in Minneapolis, Minnesota, this highway carried travelers from the northern Midwest to the Black Hills of South Dakota and Yellowstone National Park.
Custer Battlefield Highway U.S. 14, U.S. 87 Beginning in the Black Hills region, this highway headed west to Gillette, Buffalo, and Sheridan, before jogging northwest to Glacier National Park in Montana.
Yellowstone Highway U.S. 20, U.S. 87 This highway took travelers from Denver, Colorado, north to Cheyenne and Casper before turning northwest toward Yellowstone National Park. Wyoming 219 (old U.S. 87) north of Cheyenne is today known as Yellowstone Road and Business U.S. 20-26 is Yellowstone Highway.
Billings-Cody Road Alternate U.S. 14 Old U.S. 420 from Cody to Frannie
National Parks Pike U.S. 16, Interstate 90 Beginning at the point where Interstate 90 enters Wyoming from South Dakota, this “pike” followed modern Interstate 90 (not U.S. 14) all the way west to Buffalo, then following U.S. 16 west to Yellowstone National Park.
National Park to Park Highway U.S. 87, U.S. 20 This highway followed the exact routing of the Yellowstone Highway, except it entered Shoshoni directly. At that time, the Yellowstone Highway bypassed Shoshoni.
Rocky Mountain Highway Various This highway entered Wyoming along the route of current U.S. 287. At Laramie, the RMH turned southwest along Wyoming 230 to Jelm. Rather than enter Colorado as Wyoming 230 does today, the RMH cut across the southern tier of the Snowy Range, reconnecting with Wyoming 230 southeast of Encampment. The RMH continued north along Wyoming 130 and Wyoming 230 to Walcott, then followed U.S. 287 northwest to Yellowstone National Park.

In 1916, the first Federal Aid package was passed for new highway construction. The following year, a State Highway Commission was established to handle the increasing number of named highways in Wyoming. The state was authorized to accept federal aid on a matching basis. $2.8 million in matching funds were overwhelmingly approved by the Wyoming voters in April 1919. Another bond issue came in 1921; it was worth $1.8 million.

The following year, the state instituted a program of numbered state highways to make sense out of the increasingly chaotic named highways. This came amid a drastic increase in statewide car registration (In 1918 there were 15,900 cars in Wyoming. By 1920 there were 24,800 cars, and by 1930 there were 62,000 cars).

With the increased number of registered car owners came increasing hordes of travelers. Confusion over the named highway system was commonplace in the early to mid-1920s, since several named routes overlapped each other and signage was poor. Competing proponents of named routes were known to even sabotage competing named highway routes.

Finally, in 1922, the state of Wyoming decided to develop and maintain a numbered system of state highways. While not entirely replacing the named highways, the numbered routes made directions much easier to follow.

The Original Wyoming State Highway System (1922)

In 1922, the state of Wyoming commissioned, for the first time, a numbered route system. The numbering system did not follow any kind of pattern, except that most routes had numbers that ended in “0,” “1,” or “5.”

When the U.S. route numbering system was implemented in 1926, most of the original Wyoming state routes gave way to the new system. A few routes, such as Wyo. 65 and Wyo. 70, remained in service for several years after 1926, but all of the original state highways were renumbered by the 1950s.

This list shows each route number followed by a description of where the route used to go.

  (1) I-80 from Utah State Line near Evanston to Walcott Junction
  (2) U.S. 30 from Walcott Junction to Nebraska State Line near Pine Bluffs
11 (1) U.S. 85 from Colorado State Line to Cheyenne
  (2) I-25 / U.S. 87 from Cheyenne to Casper
  (3) U.S. 20-26 from Casper to Shoshoni
  (4) U.S. 20 from Shoshoni to Greybull
  (5) U.S. 310 from Greybull to Montana State Line
12 (1) U.S. 87 from Montana State Line to Sheridan
  (2) U.S. 14 from Sheridan to South Dakota State Line
13 (1) U.S. 16 from Worland to Newcastle
  (2) U.S. 85 from Newcastle to South Dakota State Line
15 U.S. 191 from Rock Springs to Moran Junction
22 Wyo. 116 from Upton to Sundance
25 (1) U.S. 30 from Granger Junction to Border
  (2) Wyo. 89 from Border to Idaho State Line
  (3) U.S. 89 from Idaho State Line to Alpine Junction
  (4) U.S. 26 from Alpine Junction to Idaho State Line
  (5) Wyo. 22 from Idaho State Line to Jackson
26 U.S. 14-16-20 from East Entrance Yellowstone National Park to Greybull
28 U.S. 26 from Diversion Dam Junction to Riverton
30 U.S. 85 from Cheyenne to Newcastle
31 U.S. 26 from Dwyer Junction to Nebraska State Line east of Torrington
35 U.S. 189 from Frontier to Daniel
36 (1) U.S. 14A from Cody to Lovell
  (2) Wyo. 114 from Lovell to Deaver
40 I-25/U.S. 87 from Colorado State Line to Cheyenne
41 U.S. 20 from Orin Junction to Nebraska State Line
50 U.S. 287 from Colorado State Line south of Tie Siding to Laramie
60 Wyo. 34 from Bosler to Wheatland
65 Wyo. 89 from Evanston to Utah State Line
70 (1) Wyo. 130 from Walcott to Saratoga
  (2) Wyo. 230 from Saratoga to Laramie
71 (1) Wyo. 220 from Muddy Gap Junction to Casper
  (2) U.S. 87 from Casper to Sheridan
80 U.S. 287 from Rawlins to South Entrance, Yellowstone National Park
81 Wyo. 789 from Lander to Shoshoni
91 Wyo. 120 from Meeteetse to Cody

The new state highway system ushered in a new era of highway designation. In fact, only a few years passed before the United State highway system was commissioned. Many of Wyoming’s state highways were renumbered in 1926 to correspond to the national system. The original Wyoming highway designations were cosigned with the new U.S. routes until the 1930s.

Meanwhile, the roads in this era were dirt or gravel. Wyoming began an aggressive program to oil several of the major arterial highways in the southeast corner of the state — Albany, Carbon, Goshen, and Natrona Counties. This program was completed in 1929 with the oiling of 87 miles of roads.

The Federal Bureau of Public Roads oiled the loop road in Yellowstone National Park in 1927. This road, commonly called the Grand Loop Road, had been maintained by the federal government since it was first surveyed. The National Park Service continues to maintain this road today. Since the loop road is maintained by the NPS and not by the Wyoming Department of Transportation, it is not part of the U.S. Highway System. U.S. 20, in fact, has an official gap in its transcontinental journey, with a break in Yellowstone National Park.

The state of Wyoming finished oiling the major roads in Wyoming by 1939. This marked the end of the remoteness and lengthy delay in communication that had plagued the state since its territorial days. Around the same time, in 1936, the state also participated in a nation-wide “Great Recommissioning” of U.S.-numbered highways. Several shorter routes were consolidated into longer-distance routes that traversed several states.

In Wyoming U.S. route history, no time period affected the way the U.S. routes looked more than 1934-1936. Of course, the Interstates did a good job of changing their appearance, but they came on the scene much slower.

Routes such as U.S. 12, 14, 87E, 87W, 116, 185, 216, 285, 287, and 420 came and went that year. The fallout lasted for several years later, as the Wyoming Highway Department and AASHTO determined which routes belonged in the system. Much of the recommissioning was planned in 1934, and much of the re-signing was completed by 1936. The histories of all of those routes that were affected by this recommissioning put together a much larger story that shows the change in thinking in U.S. route numbering.

Prior to 1934, AASHTO (the American Association of State Highway and Transportation Officials) felt that three-digit U.S. routes were connectors rather than major routes in and of themselves. U.S. 116, 185, 216, 320, 420, and so on were all rather short and intra-state, serving destinations close to but not along the immediate route of the parent highway. In addition, AASHTO liked split routes and disliked multiplexed routes.

Then AASHTO changed its mind on such issues. Although it officially did not change its rules until 1964, it started to phase out split routes in 1934 and to allow for longer three digit U.S. routes. Wyoming made several dramatic changes that year, but it is not clear to me if AASHTO recommended them, the state highway department recommended them, or if the federal government made the changes. Either way, the “Great Recommissioning of 1934-1936” dramatically changed the way the U.S. Route landscape looked between 1926 and 1982, the last year of a major U.S. highway re-routing in Wyoming.

After 1936, better signage, maintenance, and automobiles improved the traveling experience for the general public. Some highways were renumbered, but most of the statewide change occurred with further increases in traffic. U.S. 30, which followed the route of the original Lincoln Highway through southeastern Wyoming, became part of a major coast-to-coast route.

The next major development in Wyoming roads came in 1947, with the first design of the Interstate highway system. Federal funding was made available for this system in 1956, and Wyoming was granted three Interstate highways totaling over 900 miles in length. The major arterials in Wyoming — U.S. 14, 30, and 87 — were to be replaced with “superhighways” with limited access and high speeds. Interstates 90, 80, and 25 replaced these roads.

By the early 1980s, the Interstate highway system had been completed in Wyoming. Interstate 90 north of Sheridan was the last section to be finished, linking Lodge Grass, Montana, and Ranchester. At the same time, the old U.S. routes were either routed directly onto the Interstates or left on the old roads. Old sections of U.S. highway that were left behind when the old road was placed on the new road were either reverted to state and local control or lost to the ravages of Wyoming weather.

Old Yellowstone Highway

The Old Yellowstone Highway was replaced by modern U.S. 20 between Casper and Thermopolis. All photos are copyright Mike Jamison, and he has allowed AARoads to reproduce them here.

The “Park to Park” was part of the “Yellowstone Highway,” which ran Denver, Casper, Thermopolis, East Entrance Yellowstone Park. The “Yellowstone Highway” was established first but was absorbed by the “Park to Park,” which initially ran an extension from the “Yellowstone Highway” in Denver to Mesa Verde, Co. The “Park to Park” soon connected all major western national parks and in doing so, the “Yellowstone Highway” lost prominence but not its name, which still described the Denver-Yellowstone route.

The following two pictures show the Powder River bridge along the Old Yellowstone Highway bed, about 60 miles west of Casper. There’s an old Exide sign and a bull wheel nearby, plus the usual complement of bottles and curious debris.

Rocky Mountain Highway

The Rocky Mountain Highway followed U.S. 287 across Wyoming. the “Rocky Mountain Highway” route was originally considered for admission to the “Park to Park Highway,” but was rejected by the highway’s association around 1920. The “Rocky Mountain Highway” then became an independent entity to compete with the Yellowstone/Park to Park system. These next two pictures show the Rocky Mountain Highway (U.S. 287/Wyoming 789) near Jeffrey City. All photos are copyright Mike Jamison, and he has allowed AARoads to reproduce them here.

Much of this information is researched by Mike Jamison from Lee Whiteley’s book The Yellowstone Highway, Denver to the Park, Past and Present.

Page Updated September 22, 2005.