Converse County Oil & Gas Drilling

February 27, 2026 — A federal district court ruled that the Bureau of Land Management (BLM) did not follow the law when it approved the massive, 5,000-well Converse County Oil & Gas Project in Wyoming’s Powder River Basin, finding that the agency failed to properly study reasonable alternatives that might reduce environmental harm—such as slowing the pace of drilling or requiring stronger measures to limit greenhouse gas emissions.

The Court granted Advocates for the West’s motion for summary judgment as well as our request to vacate key approval documents, sending them back to the agency for a more thorough environmental review and halting the approval of any new drilling permits that rely on those documents. The decision requires BLM to revisit the project with a fuller examination of how development could affect air quality, climate, wildlife, and other natural resources—and whether less harmful options are available.

December 19, 2025 — Advocates for the West filed a reply in support of our Motion for Leave to file Second Amended and Supplemental Complaint.

November 5, 2025 — Advocates for the West filed a supplemental complaint challenging an attempt by the BLM to sidestep a 2024 court order halting the Converse County Oil & Gas Project in the southern Powder River Basin of Wyoming and unlawfully expedite development of new wells. Despite the Court’s September 2024 ruling blocking approval of additional drilling permits that relied on flawed groundwater modeling, this August, BLM again began approving drilling permits in the Converse County Project area. BLM approved these permits with minimal environmental review and no public process. It also continued to rely on a flawed groundwater analysis, and repeated other legal errors at issue in conservation groups’ initial lawsuit.

In the September 2024 ruling, the Court held that the BLM’s approval of the Converse County Oil & Gas Project was illegal because the agency’s groundwater modeling contained a major error and grossly underestimated the depletion of groundwater by the massive oil and gas project. In June 2025, the BLM issued a new groundwater analysis purporting to fix the error found by the court, but doubling down on other flawed assumptions that underestimated the project’s groundwater usage.

Now, BLM is trying to sidestep federal environmental laws by unlawfully segmenting its environmental review obligations into piecemeal, bare-bones analyses. This means that its new drilling permit approvals fail to take any meaningful look at the cumulative effect of oil and gas drilling in this area, despite the interrelated nature of the activities and their environmental effects on wildlife, air quality, groundwater, the viewshed, and the community.

October 25, 2024 — Advocates for the West filed our remedies brief, arguing that the Court should vacate the Converse County Oil and Gas Project Environmental Impact Statement and Record of Decision after ruling that the Bureau of Land Management’s groundwater modeling contained major errors and grossly underestimated the depletion of groundwater.

September 13, 2024 — A federal district court ruled that the Bureau of Land Management’s approval of the 5,000-well Converse County Oil and Gas Project in eastern Wyoming was illegal because the agency’s groundwater modeling contained major errors and grossly underestimated the depletion of groundwater by the massive oil and gas project. Drilling in this area has also already had a major negative impact on local communities, including impacts to lands, air, wildlife, and water. The Court blocked the approval of additional drilling permits in reliance on the flawed Environmental Impact Statement while the final remedy is being decided.

May 16, 2024 — Advocates for the West filed our reply in support of summary judgment and response to cross-motions for summary judgment.

January 26, 2024 — Advocates for the West filed our summary judgment brief.

July 14, 2023 — Staff Attorneys Sarah Stellberg and Hannah Goldblatt along with Senior Attorney Todd Tucci traveled to Washington, D.C., where Sarah presented oral argument before the United States District Court for the District of Columbia in support of our motion for preliminary injunction.

March 13, 2023 — Advocates for the West filed our motion for preliminary injunction and supporting brief, along with five supporting declarations, to halt any further oil and gas development in the Converse County project area.

September 7, 2022 — Advocates for the West filed a lawsuit against the Bureau of Land Management targeting the Converse County Oil & Gas Project in the southern Powder River Basin of Wyoming.

The massive 5,000 oil well project, approved under the Trump administration, is projected to have a major impact on air quality locally and regionally, including in treasured landscapes of neighboring national parks. The Delaware-sized industrial project will also create irreversible negative impacts to wildlife through special exemptions from traditional habitat protection measures. Overall, the project threatens the survival of sage grouse and birds of prey throughout the project area.

A key claim in the lawsuit challenges the Bureau’s refusal to regulate “Fee/Fee/Fed” wells in the project area, which are wells that drill directionally into federal minerals from adjacent non-federal lands. This illegal Bureau practice allows fossil fuel companies to extract publicly-owned minerals without common-sense environmental protections. The Converse County project consists predominantly of Fee/Fee/Fed wells.