General William Raynolds, who named Union Pass and traveled with Jim Bridger, wrote in 1860:”Here I desire to state a fact of some importance with reference to the nomenclature of the Big Horn and its branches.The river which last summer we descended under the name of the Big Horn is formed by the junction of the Popo-Agie and the Wind River at this point, and should properly be called the Big Horn below the site of our present camp. By the trappers, however, it is always spoken of as the Wind River until it enters the caňon some 30 miles below here. There is no good reason for this arbitrary distinction, whereby the same stream passes into the mountains under one name and emerges with another, and it is necessary that these facts be known to avoid confusion.”