Big Tree Register


From the depths of the Shawnee National Forest to backyards in the suburbs of Chicago, Illinois’ biggest trees are branching out. The register inspires generations of big tree hunters who relish the opportunity to find and nominate the next champion tree. 

Explore the Map of Champion Trees

The map includes tree species details, GPS coordinates, measurements, and their resulting scores, as well as a list of the 10 largest trees on record to date. Big tree enthusiasts can use the map to track down Illinois’ top-ranked tree, a 122-foot tall Eastern Cottonwood in Ogle County, and the county with the most champion trees, Union County in Southern Illinois.

The register began in 1962 as a citizen-science outreach project to recognize the Prairie State’s largest native trees, and anyone with a tape measure can nominate a tree. 

Illinois forests have grown older and more mature over the past century. Since 1924, forest coverage has increased by 67%, Hayek says. Research has shown that large, old trees grow faster and pull more carbon dioxide from the atmosphere than young trees. With more cracks, notches, and hollows, large trees provide shelter for many species of birds, mammals, and other wildlife. For homeowners, large trees increase property value, reduce energy bills, and add privacy.

Want to nominate a tree? 

Use the following materials to measure and nominate a tree.