Modern Rodeo is said to have originated in Nebraska? 

In 1882 William F. "Buffalo Bill" Cody, then a North Platte resident, staged a rodeo-type event called the "Old Glory Blowout." The following year he presented a show in Omaha called the "Wild West Combination." Many people believe that the Old Glory Blowout was the first rodeo in the United States. Whether or not this claim is true, the performances organized by Cody in North Platte and Omaha marked the beginning of his hugely successful Wild West show.

Buffalo Bill's Wild West Historical Sketches and Programme, 28/9/3
Source: Mrs. E. O. Haschenburger, Lincoln, 8751-13

"Buffalo Bill's Race for Gold," Buffalo Bill Library, NO. 431, Aldine Press, London, 1899-1930
Source: Nebraska State Historical Society, no # Comic

"Buffalo Bill & The Mormons," Buffalo Bill Library, No. 432, Aldine Press, London, 1899-1930
Source: Nebraska State Historical Society, no # Comic