Chelsea E. O'Sullivan

O'sullivan, Chelsea E.
Chelsea E. O'Sullivan is an associate in the Environmental Group, where she assists clients in regulatory compliance, permitting, enforcement action response, and transactional environmental due diligence. Chelsea's practice focuses on the Clean Water Act, the Clean Air Act, the National Environmental Policy Act, the Comprehensive Environmental Response, the Compensation and Liability Act, and other federal environmental statutes and their state analogues.

Chelsea helps clients evaluate the unique risks and challenges associated with the interaction of tribal law, federal Indian law, and environmental law. Specifically, she advises clients on the tribal law and federal Indian law implications of siting and permitting infrastructure projects.

Chelsea earned a J.D. from University of Virginia School of Law, where she was the editor-in-chief of the Virginia Environmental Law Journal. She holds a B.S. in Environmental Science, summa cum laude, from Saint Mary's College of California.




  • J.D. University of Virginia School of Law 2015
  • Editor-in-Chief, Virginia Environmental Law Journal

    Dillard Fellow

  • B.S. Environmental Science summa cum laude Saint Mary's College of California 2012

Bar Admissions

  • California
  • District of Columbia


  • Recognized as a Rising Star in the Washington, DC edition of Super Lawyers, 2020