On July 5, 1840, in the presence of 2,000 Indians, trappers, and traders, Father Pierre-Jean De Smet (1801–1873) offered the first
Catholic Mass on a point overlooking Horse Creek and the Green River in what is now Wyoming on an altar of native stone decorated with wild flowers.
In Fr. De Smet's words, "It was a spectacle truly moving to the heart of a missionary that this immense family, composed of so many different tribes, should prostate
themselves before the Divine Host."
In October of 1881, a young priest named Father Michael J. McGivney called together a small group of men to meet in the basement of St. Mary's Church in New Haven, Connecticut. His purpose was to help Catholic men remain steadfast in their faith, promote closer ties of fraternity among them, and set up a system that would help fellow members and their families in times of hardships. The men of this fledgling organization were chartered on March 29, 1882, to be known as the Knights of Columbus in honor of Christopher Columbus, the Catholic discoverer of America.
In 1903 a group of Catholic men gathered in Cheyenne for the purpose of planting the seeds of Columbianism in Wyoming. On July 12, 1903, the first Knights of Columbus council in the state of Wyoming was chartered in Cheyenne. Four years later, still with only a single council in the state, the Knights were placed under the supervision of Territorial Deputy J. H. Conway, a resident of Cheyenne and a prominent benefactor of St. Mary's Cathedral. Dr. Conway led the Wyoming Knights for the next nine years.
Local councils held a convention on June 5, 1920, in Casper. A State Council was organized on July 30, 1920, and Wyoming's first state deputy, Charles A. Cullen, took office the following year.
A monument at the site of Fr. De Smet's first Mass near Daniel, Wyoming, was erected in 1925. The site, known as "The Prairie of the Mass," is on the National National Register of Historic Places (Wyoming Place No. 38). A Commemorative Mass is offered there annually on the second Sunday of July. In 2012, the Knights of Columbus raised the funds necessary to pay for the monument to be re-roofed.