The Yager’s collections comprise over 20,000 items, including North American Indigenous artifacts, European and American fine art, Pop Art, and material culture artifacts.

Willard E. Yager’s Upper Susquehanna Collection is perhaps one of the best documented regional archaeological collections in New York State.  Other important ethnographic collections include Southwestern Native American and South American artifacts.

Louis van Ess, an Episcopal minister and Hartwick professor, bequeathed a significant collection of Italian Renaissance paintings and Russian icons, as well as important American paintings by Frederick Childe Hassam, Homer Dodge Martin, Ralph Blakelock and John Henry Twachtman.

The Museum has also added works by Rockwell Kent, Alexander Calder, Robert Rauschenberg, and Andy Warhol to the collection over the years.