 As a trustee of Amherst from 1897 and 1921, Pratt contributed funds for a gymnasium, dormitory, and other buildings.He was the first alumnus to donate a building to Amherst College—the Pratt Gymnasium was erected in 1883, and was reconstructed as the Pratt Museum in 1942.Following further rebuilding, it reopened in August 2007 as the Charles M. Pratt Dormitory.