The Morton Arboretum in Lisle, Illinois, is a 1,700-acre public botanical garden, outdoor museum, and major scientific institution devoted to trees. Founded in 1922 by Joy Morton on the grounds of his Thornhill estate, it grew from a family deeply linked to Arbor Day into a center for recreation, education, research, and conservation. Its collections include more than 4,100 plant species and over 200,000 cataloged plants, alongside trails, roads, gardens, and the pioneering Schulenberg Prairie restoration. Through its Center for Tree Science, library, educational programs, and global conservation work focused on rare and threatened trees, it serves both the public and the international scientific community.