In the spring of 1965, Pax and Villa Irvine held a party in their home in Buffalo for a large number of guests. Among those present were two ex-Californians, Robert Burnquist and George Johnson, who had recently invaded Johnson County. By virtue of their origin and for their mutual protection, they were more or less attracted to each other.
 
During the course of the evening, the two, in conversation with the host, Pax Irvine, were lauding the beauties of the country and asked him if there had ever been any discussion about an organized trail ride in the Big Horn Mountains. Pax said that it had been considered in the past, but for some reason failed to materialize, but he for one would certainly and enthusiastically support the idea.
 
With this as a starter, Burnquist and Johnson discussed the idea with other acquaintances in the area and were met with universal enthusiasm. The outgrowth of these conversations culminated in a meeting at the American Legion Club in Buffalo, Wyoming, on April 7, 1965.

Present at the meeting were the twelve original organizers: William Paxton Irvine, Russ E. Miller, Kenneth M. Schiffer, C.R. Burnquist, Kelly Howie, Dr. John A. Knebel, William J. Kirven, L.V. Stafford, A.J. Barker, John R. Christian, R.E. Jones, and George Johnson.

These gentlemen adopted articles of incorporation and bylaws for the organization which were fashioned (or stolen) from the Rancheros Visitadores, a “Trek” in Santa Barbara, California.  On June 28, 1965, the Articles of Incorporation for the Big Horn Mountain Roundup were filed with the State of Wyoming.  One of the stated purposes of the corporation was to “promote the social welfare of its membership and to increase interest in, and knowledge of, the historic and scenic areas in the immediate vicinity of the Big Horn Mountains of Wyoming.”

The first applications for the ride were three pages long and required that the applicant state whether he was accustomed to taking care of his own horse and whether it was his own or rented.  The applicant was also required to submit a black and white photograph (of himself, not his horse) in complete western attire.  Most of the original directors just used the posters of themselves found in the post office.