The University of Idaho Herbarium began with the collections of Louis F. Henderson (1853-1942). Henderson, who had been employed at the USDA experiment station in Moscow, became the university’s first botanist and herbarium director in 1889 with the establishment of the University of Idaho. The initial collection of over 10,000 specimens was housed in the University of Idaho Administration building. Between 1889 and 1906, the collection grew to over 85,000 specimens and was considered one of the best in the Pacific Northwest. On March 30, 1906 the Administration building was destroyed by fire and the majority of the collection was lost. Shortly thereafter, in 1911, Henderson left Moscow for the University of Oregon, where he continued his extensive contributions to our knowledge of the flora of the Pacific Northwest, earning him the title of “The grand old man of botany of the Pacific Northwest.”
Growth of the University of Idaho Herbarium was slow following Henderson's departure. Notable botanists such as William H. Baker and J.H. Christ continued to explore the flora of the area, contributing to the growth of the herbarium, and by the mid 1900s the collection had grown to about 50,000 specimens.
The Charles R. Stillinger Trust was established in 1972, allowing funding for the procurement of specimens and increased herbarium management. Under the directorship of Douglass M. Henderson from 1972-1996, the University of Idaho Stillinger Herbarium more than doubled in size.
Following Henderson’s untimely death in 1996, the herbarium saw several directors, however; it was not until 2001, when Pamela Brunsfeld a former student and herbarium assistant of D.M. Henderson was hired as the Collections Manager. Under Pamela's leadership, an active collections and curation program involving undergraduates and graduate students was reborn that continues today.
In 2007, the herbarium was moved from the Department of Biological Sciences to the College of Natural Resources. In 2008, David C. Tank joined the faculty of the College of Natural Resources, and he serves as the current Director of the Stillinger Herbarium.