Work on U.S. 20/Wyo 789 through Wind River canyon began in 1922 and was finished in 1924, replacing the Bird's Eye Pass Route over the Owl Creek Mountains.[3] U.S. 20/Wyo 789 travels through the canyon, at times level with the canyon floor. The scenic route offers views of the canyon and landmark natural structures like the Chimney Rock. The canyon is at times as much as 2,500 feet (760 m) feet deep. The change in elevation between the Bighorn Basin and the Wind River Basin is about 300 feet (91 m).[4]
The Wind and Big Horn flow north out of Boysen Reservoir, through the canyon, into Thermopolis, and onward to points north.
Geology
The canyon cuts through a comprehensive set of Wyoming rock strata exposures. Many of these are noted on roadside signs. The canyon was cut in the established course of the Wind River, which predates the uplift of the Owl Creek Mountains. The water gap was created as the topography of the mountains was raised over the past two million years from previously flat terrain. From south to north, the canyon crosses an area of complex faulting, then narrows as it descends into Precambrian rocks at three road tunnels. Beyond the tunnels, the strata dip, with high cliffs of sedimentary Madison Limestone, Bighorn Dolomite and sandstone. The northern end of the canyon cuts through red sandstone of the Chugwater Formation.[5]
