Senior Staff Attorney
Denver Office

1660 Wynkoop Street, Suite 1150

Denver, CO 80202


Mason Cummings, TWS

Connect with Gregg

Gregg joined The Wilderness Society in 2023 as a Senior Staff Attorney.

Gregg is a Senior Staff Attorney focusing on renewable energy, the just transition from extractive economies, and the Mojave desert and Southern California mountain landscapes.

Prior to TWS, Gregg worked fourteen years in private practice representing tribal nations in federal and state court to protect their rights and interests in land, water, and cultural resources and enforce the federal government’s tribal trust responsibilities. He also worked as in-house counsel for a tribe in Arizona.

Growing up in southern California, Gregg often hiked and explored the nearby San Gabriel and San Bernardino Mountains and developed a deep appreciation for the outdoors.  He received a B.A. from the University of California at Santa Barbara and a J.D. from the University of Colorado School of Law, where his research for a public lands and federal Indian law professor shaped his thinking about public land management and set the course of his legal career.

Gregg lives with his wife in Denver, Colorado.