Patrick R. Day - Holland & Hart LLP

Patrick R. Day

Listed in Best Lawyers since 2003
Phone: 307-778-4200

With significant trial, administrative, and appellate experience before the Wyoming Supreme Court, and in the Ninth, Tenth, and District of Columbia Circuit Courts of Appeal, natural resource and energy companies engage Mr. Day when faced with high stakes litigation. Clients trust his advocacy skills to achieve positive results when their businesses are on the line.

Mr. Day represents coal producers, oil and gas companies, pipelines, refineries, power plants, and gas plants. He represents energy companies in environmental litigation in state and federal courts around the country as well as before state agencies. His experience includes coal contract disputes, oil and gas disputes, class actions, ad valorem and severance tax disputes, and environmental permitting and appeals. Mr. Day also works as an arbitrator and mediator.

In February 2012, Mr. Day argued before the U.S. Court of Appeals, District of Columbia Circuit, for a coalition of industry groups taking part in the challenge to the EPA's endangerment rule, which focuses on EPA's initial decision holding that greenhouse gases are harmful, and the tailpipe rule, which adopts new standards for car and light-truck emissions. A decision is expected in the next several months.

Mr. Day has briefed and argued a successful challenge to the constitutionality of Wyoming's ad valorem tax scheme and has represented numerous energy clients in Wyoming tax valuation litigation.

Mr. Day is admitted to practice in Wyoming, as well as the Ninth Circuit Court of Appeals, the Tenth Circuit Court of Appeals, and the District of Columbia Circuit Court of Appeals. He has appeared before the Wyoming Supreme Court on numerous occasions over the last twenty-five years.

University of MichiganBA University of Wyoming J.D.

Case History

Exxon Mobil Corporation v. Wyoming Department of Revenue, 2009 WY 139 (2009) — Obtained reversal in the Wyoming Supreme Court of an adverse decision by the Wyoming State Board of Equalization determining the point of valuation for ad valorem and severance taxes for natural gas production from Exxon Mobil Corporation''s multi-billion dollar natural gas processing facility.   This decision represents the latest in a string of favorable rulings obtained for ExxonMobil in a series of tax cases dating back about 12 years.  The decisions have collectively saved ExxonMobil and major Wyoming gas producers tens of millions of dollars as the State has attempted to raise taxes by advocating aggressive new statutory interpretations.
Basin Electric Power Cooperative Air Permit Appeal, Docket No. 07-2801, Environemental Quality Council, State of Wyoming — Successfully defended the issuance of a new PSD Air Quality Permit for the construction of a new coal-fired electric generating facility against challenges by environmental groups.  One of only a handful of new permits to survive such challenges in recent years.

Office Location

2515 Warren Avenue, Suite 450
Cheyenne, WY 82001-3162
United States


Practice Areas

Commercial Litigation
Litigation - Environmental