The preserve was formed in 2000 out of a transfer of excess open space that had been part of the state owned Senator Garret W. Hagedorn Psychiatric Hospital. The hospital first opened in 1907 as the states Sanatorium for Tuberculosis Diseases, were patients benefited from good clean air and access to the outdoors. Today the Hagedorn Psychiatric Hospital facility is closed and decommissioned, but the elements of open space and clean air remains a benefit for all to appreciate. The mostly forested area includes large plantations of Norway spruce and white pines, likely planted in the 1930s as part of watershed conservation projects. The values of this work are evident in the clear water of Rocky Run, whose water helps supply Spruce Run Reservoir. Interestingly, portions of Hagedorn were even once a "State Game Refuge". Impacts to the forest community from invasive non-native plants like Japanese barberry and Japanese stiltgrass are severe in many areas. However the rocky, thin soiled, mountain top areas that were historically never cleared for farming remain relatively free of invasive plant infestations and offer a glimpse of the unique beauty of the oak and tulip forest.