Mark J. Mathews

Mark J. Mathews



Concentrates on oil and gas, carbon management, environmental contamination and land use law. Involved in many of the major disputes facing the energy industry in Colorado.

Mark Mathews has successfully represented oil and gas and mining clients and real estate development companies in litigation and regulatory rulemakings concerning oil and gas preemption and royalty issues, hazardous waste contamination, enforcement of oil and gas regulations, zoning and development disputes and land use permitting issues.

Mark represents real estate development companies, lenders and borrowers on environmental matters, including contaminated properties, remediation of hazardous substances and environmental liability issues. He counsels real estate interests and lenders involved in transactions relating to soil, groundwater and air contamination, and, most recently, per- and polyfluoroalkyl (PFAS) contamination.

Mark is also outside regulatory and litigation counsel for the Colorado Oil and Gas Association (COGA) and outside litigation counsel for the American Petroleum Institute (API). He has represented COGA, API, Extraction Oil and Gas, Martin Marietta Materials and other energy companies in high-profile matters concerning operational preemption between state and local governments and challenges to Colorado Oil and Gas Conservation Commission (COGCC)—now renamed the Energy and Carbon Management Commission effective July 1, 2023—permits, state oil and gas regulations and local government land use permits. 

Mark frequently represents his clients before the COGCC and has been involved in major oil and gas rulemakings on flowline regulations, setback requirements and financial assurance regulations on behalf of COGA and individual operators.

Representative Matters


  • Successfully represented Extraction Oil and Gas in Boulder District Court against Boulder County’s challenge to Extraction’s leases. The Court ruled against Boulder’s theory that pooling restrictions in the leases precluded Extraction from pooling multiple leases, and held for Extraction on all points of law.

  • Successfully represented COGA in litigation against the cities of Lafayette, Fort Collins, and Longmont regarding bans or moratoria on hydraulic fracturing activities, prevailing on summary judgment in each matter. This litigation involved precedent-setting issues pertaining to state versus local preemption of oil and gas activities, and culminated in two rulings by the Colorado Supreme Court striking down Longmont's ban and Fort Collin's five-year moratorium on hydraulic fracturing.

  • Won a major ruling in Adams County District Court on behalf of client, Colorado Oil & Gas Association (COGA) and the American Petroleum Institute (API). COGA and API jointly filed suit to overturn a number of oil and gas regulations adopted by the City of Thornton. Colorado District Court Judge Edward Moss ruled that many of Thornton’s regulations, including its setback regulations, were illegal and operationally preempted by state law.

Oil & Gas Regulatory Rulemaking

  • Represented COGA and its member companies with respect to addressing a variety of legislative issues, including the 2019 omnibus oil and gas bill, statewide ballot measures, and local government regulations.

  • Successfully represented COGA and its members in a number of complex, multi-day rulemaking before the COGCC , including rulemakings concerning new setback requirements and new flowline regulations governing mapping, registration, removal and integrity management issues.

  • Represented several energy companies in opposing potential state-wide ballot initiatives impacting oil and gas operations. This work included devising a legal and government relations strategy to oppose twelve different ballot measures.

  • Represented COGA and several operators in the seven-month long “Mission Change” rulemaking rewriting nearly all of the existing oil and gas regulations after the enactment of SB 19-181.

Environmental Remediation

  • Represented Cotter Corporation, a large uranium production company, in the long-term remediation of its property in litigation actions with private parties, including all issues pertaining to land use and environment, surety and environmental matters. Representation included successfully defending the company in litigation brought by environmental groups regarding the remediation, negotiating a complex cleanup settlement with federal and state environmental authorities, and overseeing each step of the remediation.

  • Represents Martin Marietta Materials, the largest aggregate producer in the Western United States, on all land use and environmental issues that arise from its quarrying and manufacturing activities. This work includes representing the company in litigation and administrative proceedings pertaining to alleged air, water and waste violations, as well as zoning and permit approvals.

  • Represented numerous development companies with respect to the investigation and remediation of soil and groundwater on their sites.  Part of this representation included negotiating voluntary cleanup agreements with the Colorado Department of Public Health and Environment and different kinds of negotiated documents with the Environmental Protection Agency, including Bona Fide Purchase Agreements protecting the client from ongoing liability.

Insights & Publications




  • J.D., Stanford Law School, with high honors
  • B.A., Yale University, magna cum laude


  • Colorado
  • District of Columbia
  • California


American Bar Association

California Bar Association

Colorado Bar Association

Denver Bar Association

District of Columbia Bar Association

Community Involvement


Board of Directors, Global Dental Relief

Executive Board, Aurora Economic Development Council

Board of Directors, American Red Cross, Mile High Chapter



"Mark is very well respected. He's done a lot of complicated and excellent risk management work." – Chambers USA, 2023

"He is incredibly professional and prepared. His level of service to clients is top-notch and he is an amazing asset and is wonderful to work with." "He's a well-regarded litigator and a very excellent lawyer in the space. He's very collaborative to work with. He is persistent and hard-working and represents clients well."  – Chambers USA, 2022

5280 Top Lawyers, 2015-2024

Best Lawyers in America, 2014-2024

Colorado Super Lawyers, 2012-2013, 2018-2019

Chambers USA, 2010-2024

Lawdragon, 500 Leading U.S. Energy Lawyers, 2021, 2023

Influencers: Law, The Business Journals, 2018

Who's Who in Energy, Denver Business Journal, 2015-2018

Powerbook Top Ten Newsmaker Award, Denver Business Journal

American Red Cross Volunteer Leadership Award, 2017

Editor, Stanford Law Journal

Articles Editor, Stanford Environmental Law Journal