In 1990, Henley founded the Walden Woods Project to help protect "Walden Woods" from development. The Thoreau Institute at Walden Woods was started in 1998 to provide for research and education regarding Henry David Thoreau. In 1993, a compilation album titled "" was released, with a portion of the royalties from the sales going to the Walden Woods Project. In 2005, he had a fundraiser concert with Elton John and others to buy Brister's Hill, part of Walden Woods, and turn it into a hiking trail.