| State: | WY |
| Type: | WY |
| Route: | 91 |
| Alternate Name: | Cold Springs Road |
| Map Custom: | yes |
| Map Notes: | WYO 91 highlighted in red |
| Length Mi: | 23.10 |
| Length Round: | 2 |
| Length Ref: | [1] |
| Direction A: | West |
| Terminus A: | near La Prele |
| Junction: | near Douglas |
| Direction B: | East |
| Terminus B: | in Douglas |
| Counties: | Converse |
| Previous Type: | WY |
| Previous Route: | 90 |
| Next Type: | WY |
| Next Route: | 92 |
Wyoming Highway 91 (WYO 91) is a 23.1-longNaN-long Wyoming state highway in south-central Converse County southwest of Douglas. The highway is locally known as Cold Springs Road.
Wyoming Highway 91 begins its western end at Converse County Route 11 southwest of La Prele and near the Medicine Bow National Forest boundary. Highway 91 changes to Converse County Route 24 south of there. Highway 91 proceeds northeast as Cold Springs Road and through the community of La Prele. As Highway 91 nears Douglas, the road turns north and meets the eastern terminus of Highway 96 at 20.08miles. Highway 96 heads west as Highway 91 turns east toward Douglas. Almost at the Douglas city limits, Interstate 25 comes into view to the north and is paralleled by Highway 91 to its end. Highway 91 reaches its eastern end at Highway 94 in Douglas, south of Interstate 25 exit 140.[2]
Wyoming Highway 91 was first designated to a stretch of present-day Highway 89 in Lincoln County.[1]
According to the original map of Wyoming State Highways in 1924, present day Highway 89 was numbered Highway 65. With the introduction of U.S. routes in 1926; The routing between Cokeville and Star Valley was renamed Wyoming Highway 89, while the section south of Sage remained Wyoming Highway 65. Highway 89 was numbered in hopes that U.S. Route 89 (which had a northern terminus in central Utah at that time) would be extended north into Wyoming.[1] In 1936, US 89 was extended into Wyoming along old Highway 287. Highway 89 was then renumbered to Highway 91 to avoid confusion between the two highways, while Highway 65 kept its original number. However, within a few years, US 89 was rerouted to its current route in Utah and Idaho, and U.S. Route 189 was created along the old portion of Highway 287. As a result, Highway 89 was redesignated over both Highways 65 and 91.[1]