Photograph of Mark Thomson


  • University of Wisconsin – Madison, B.A. (2008)
  • University of Minnesota Law School, J.D. (2012) magna cum laude, Order of the Coif


  • District of Columbia
  • Minnesota

Mark Thomson

 Associate Washington, D.C.
Phone: +1 202.624.2706
1001 Pennsylvania Avenue NW
Washington, DC 20004-2595

Mark Thomson is an associate in the firm’s Environment & Natural Resources group, where his practice focuses on litigation and appeals, enforcement, and regulatory counseling across a variety of industries. Mark has briefed and assisted with litigation involving the Clean Power Plan, Regional Haze Rule, the Stream Protection Rule, among other major EPA regulations. He has drafted comments on an array of regulations proposed under statutes ranging from the Clean Air Act to the Federal Land Policy and Management Act of 1976 (FLPMA). He has also worked with clients, contractors, and state and federal regulators to identify and resolve permitting and diligence questions arising under federal, state, and local laws.

In addition to his work as an environmental lawyer, Mark maintains an active general litigation practice. He has drafted briefs in intellectual property cases, takings actions, tariff disputes, and, especially, claims under the Administrative Procedure Act. He also has an active pro bono practice, which has included representing people seeking asylum, writs of habeas corpus, or child custody.

Mark earned his B.A., with comprehensive honors, from the University of Wisconsin-Madison. He earned his J.D., magna cum laude and Order of the Coif, from the University of Minnesota Law School, where he was a lead editor of the law review. After law school, he clerked for Judge Robert Jonker of the U.S. District Court for the Western District of Michigan, for Judge John Rogers of the U.S. Court of Appeals for the Sixth Circuit, and for Chief Judge Ed Carnes of the U.S. Court of Appeals for the Eleventh Circuit. Before joining Crowell, Mark spent a year in private practice with a large firm in his hometown of Minneapolis.


Admitted to practice: District of Columbia, Minnesota


  • "Open Minds and Harmless Errors: Judicial Review of Postpromulgation Notice and Comment," 101 Cornell L. Rev. 261 (2015). Co-Author: Mark Thomson.
  • "Method or Madness: The Leflar Approach to Choice of Law as Practiced in Five States," 66 Rutgers L. Rev. 81 (2013). Author: Mark Thomson.
  • "Who Are They to Judge?: The Constitutionality of Delegations by Courts to Probation Officers," 96 Minn. L. Rev. 306 (2012). Author: Mark Thomson.

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Feb.07.2018 DEAL NOTE: Crowell & Moring Client NRG Yield, Inc. Enters into Agreements to Acquire Gas-Fired and Solar-Generating Facilities from NRG Energy, Inc.
Nov.17.2017 DEAL NOTE: Crowell & Moring Client NRG Yield, Inc. Acquires 38 MW Solar Portfolio from NRG Energy, Inc.
Feb.28.2017 Deal Note: Crowell & Moring Client NRG Yield, Inc. Enters into Agreement to Acquire Interests in Solar Generating Facilities from NRG Energy, Inc.