Lucas “Luke” O’Brien is an associate with the Denver law firm of Trout Raley. Since joining Trout Raley, Luke has practiced water, environmental, and federal administrative law, among others, and represented a variety of public and private clients. Luke has handled matters before the Colorado district, water, and appellate courts, the Colorado Ground Water Commission, and the U.S. District Court for the District of Colorado. During law school, Luke served as the Editor-in-Chief of the Colorado Environmental Law Journal and interned for the Natural Resources and Environment Section of the Colorado Attorney General’s Office, the Environmental Protection Agency in Washington D.C., the U.S. Attorney’s Office in Denver, and Colorado Magistrate Judge Kristen L. Mix.

Legal Experience

Trout Raley, Colorado
Associate Attorney (2022 - Present).  Natural resources firm with emphasis in water and environmental law and litigation.  Represents a variety of clients including water conservancy districts, municipalities, counties, landowners, and real estate developers, and nonprofits in both state and federal litigation and administrative matters.

Schultz Wildcat Scholarship recipient for dedication and excellence in environmental law, 2022.

Gary C. Bryner Distinguished Service Award, 2022.


Colorado Courts
United States District Court for the District of Colorado

Law School Attended

University of Colorado Law School, Class of 2022

University Attended

University of California - Berkeley, Class of 2017

Associations and Memberships

Colorado Bar Association (member of Water Law Section)
Denver Bar Association


Trout Raley Montaño Freeman Sinor Thompson P.C.


1120 N Lincoln Street,
Suite 1600,
Denver, Colorado 80203-2141