The Old Mill was awarded a Level I Accreditation by The ArbNet Arboretum Accreditation Program and The Morton Arboretum, for achieving particular standards of professional practices deemed important for arboreta and botanic gardens. The ArbNet Arboretum Accreditation Program is the only global initiative to officially recognize arboreta at various levels of development, capacity, and professionalism. The Old Mill is also now recognized as an accredited arboretum in the Morton Register of Arboreta, a database of the world’s arboreta and gardens dedicated to woody plants.