The Morton Arboretum

Illinois, United States

---

The Morton Arboretum in Lisle, Illinois, was founded in 1922 by Joy Morton, president of the Morton Salt Company and son of the Arbor Day founder Julius Sterling Morton.

Originally centered on Joy Morton's Thornhill Estate, the arboretum now spans about 1,700 acres and serves as a public outdoor museum dedicated to trees and other plants from around the world. Landscape architect O.C. Simonds designed the grounds with a naturalistic style, including winding roads and paths around lakes and hills.

The arboretum holds over 3,300 plant species, boasts one of the largest herbarium collections in the country with 165,000 preserved specimens, and features a significant library of rare botanical books. It became one of the first arboreta to offer public education programs, starting in the 1940s under naturalist May Theilgaard Watts.

The site has expanded steadily, maintaining a balance between scientific research, conservation, education, and public enjoyment, including trails, gardens, research facilities, and a commitment to urban tree health through breeding efforts. It remains a leading institution that celebrates the importance of trees for the environment and human well-being.