The vast majority of historic material about UW Athletics is held by the America Heritage Center (AHC). They are not part of the University Libraries, but rather a separate organization of the university. They serve as the official repository of university records, plus hold donated papers.

The library lists the AHC collection in our catalog to assist researchers and the "University of Wyoming: Intercollegiate Athletics Records: 1920-2015" record is the best place to start: http://uwcatalog.uwyo.edu/record=b2136499~S3 

This is the link to the AHC webpage: http://www.uwyo.edu/ahc/   The best email to contact their research desk is ahcref@uwyo.edu.

In addition, the UW yearbooks (The Wyo) have all been digitized by the library and are available at this link: http://uwdigital.uwyo.edu/  Use the drop-down "Collections" menu to access the yearbooks (The Wyo).

The "Special Collections" department has some UW specific holdings such as Branding Iron newspapers.