The Morton Arboretum, in Lisle, Illinois, United States, is a public garden, and outdoor museum with a library, herbarium, and program in tree research including the Center for Tree Science. Its grounds, covering 1,700 acres (6.9 square kilometers), include cataloged collections of trees and other living plants, gardens, and restored areas, among which is a restored tallgrass prairie. The living collections include more than 4,100 different plant species. There are more than 200,000 cataloged plants.
As a place of recreation, the Arboretum has hiking trails, roadways for driving and bicycling, a 4-acre (16,000 m2) interactive children's garden and a 1-acre (4,000 m2) maze. The Schulenberg Prairie at the Arboretum was one of the earliest prairie restoration projects in the Midwest, begun in 1962. It is one of the largest restored prairies in the Chicago suburban area.
The Arboretum offers an extensive nature-centered education program for children, families, school groups, scouts, and adults, including tree and restoration professionals. The Woodland Stewardship Program offers classroom and online courses in ecological restoration techniques. The Arboretum also offers credit courses through the Associated Colleges of the Chicago Area, a regional consortium.