Stephen Sullivan

Stephen Sullivan

Main: 303-830-2500
Licensed in: Colorado, Wyoming

OverviewExperience & ResultsPractice AreasHonors & InsightsEducation & Admissions

Steve Sullivan’s experience in natural resources and the Rocky Mountain west began long before his legal career. His work on ranches in Wyoming and Nevada provides perspective when addressing land transactions and negotiations between mineral and surface owners. During the energy boom and bust of the 1970s his education included research on the supply of ground water for coal pipeline slurries, engineering of solar and geothermal homes in the Northern Rockies, uranium resource economics and supply, and geologic field work in five western states. Knowledge and relationships resulting from this experience aid in providing top notch legal representation and obtaining lasting solutions for his clients.

Steve represents clients in all aspects of natural resources with a primary focus on oil and gas exploration and development in the Rocky Mountain region. A large part of his oil and gas practice involves acquisitions and divestitures as well as operational and permitting matters. Mr. Sullivan represents mining companies from the initial staking of claims through financing, permitting, and start-up of mining operations. He also represents parties in the purchase of ranches and in the acquisition and sale of water rights in Colorado, including development of water delivery systems.

Oil and Gas:

  • Simultaneous purchase from multiple parties and sale of approximately 100 wells and 23,000 acres of producing and undeveloped natural gas properties in the San Juan Basin.
  • Multi-stage sale and agreement for joint development affecting 350,000 acres of producing and undeveloped properties in Colorado’s DJ Basin.
  • Due diligence for acquisition of 40,000 acres of undeveloped leases in Wyoming’s Niobrara shale play.
  • Practice before the Colorado and Wyoming Oil and Gas Conservation Commissions.


  • Due diligence for acquisition of mineral properties and operating mines in Colorado, Nevada, Wyoming, Utah and California.
  • Formation of mining companies, followed by location and development of uranium mining claims and subsequent consolidation, permitting, construction, operation and ultimate sale of a mine in San Juan County, Utah.
  • Due diligence for both purchase and sale of two operating coal mines in the Powder River Basin, Wyoming.


  • Due diligence for acquisition of 588,000 acre Vermejo Park Ranch and negotiation of subsequent mineral development agreements.
  • Purchase of land and water rights for an 80,000 acre Colorado ranch, followed by timber management negotiations, ranch management issues and creation of a conservation easement.
  • Sale of 2,500 acre Garfield County (Colorado) ranch and mineral rights to major oil and gas company.


  • Acquisition and management of multiple Rocky Mountain Fuel properties in Colorado, including surface leases, water rights, mineral rights, and coal and oil and gas royalties, covering approximately 32,000 acres.
  • Due diligence for acquisition of wind power properties and easements in eastern Colorado.
Practice Areas
  • Oil & Gas Transactions
  • Oil & Gas Conservation Commission and Regulatory
  • Real Estate
  • Acquisitions & Divestitures
  • Land Use
  • Mineral Title Examination
  • Local Government
  • Water Rights
  • Mining
  • Public Lands
  • Renewable & Alternative Energy
  • Corporate Law
Honors & Insights
  • Steward of Industry Award, Denver Section of the Society of Petroleum Engineers (“SPE”), 2018
  • Top Lawyers, Natural Resources, 5280– The Denver Magazine, 2017-2021
  • Board Member, The Colorado Oil and Gas Association (1995-present)
  • Mayor of the Town of Foxfield, 2002-2008
  • Board Member, Town of Foxfield, 1998-2008
  • Board Member, Volunteers for Outdoor Colorado, 1990-1994
  • Distinguished Service Award, Rocky Mountain Association of Geologists, 1990
  • B.A. in geology, Princeton University, magna cum laude, Sigma Xi, 1977
  • U.S. in Energy and Resources, University of California, Berkeley, with honors, 1979
  • J.D., University of Denver, with honors, 1982
Bar Admissions / Qualifications
  • Colorado, 1982
  • Wyoming, 1996
  • U.S. District Court, District of Colorado, 1982
  • U.S. Court of Appeals, Tenth Circuit, 1982