Wyoming · Area of Critical Environmental Concern
Big Sandy Openings ACEC
BLM found a wildlife resource, a scenic value and a natural hazard here, and its plan calls for special management. BLM's records place 2 rights of way inside the line today, and three grazing allotments cover part of it. It covers 1,994 acres and was designated December 22, 2024, in the Rock Springs Resource Management Plan.
One of the 1,120 places the Bureau of Land Management has designated an Area of Critical Environmental Concern. This page shows its line, what BLM found there and what sits inside it.
Plan in motion
Rock Springs RMP amendment names this area among the ACECs it covers. BLM's notice of October 2, 2025 says:
The BLM will re-evaluate the existing designations for ACECs, SRMAs, and the NHT corridor to assess whether special management is needed to protect sensitive resource values and whether mineral development can be allowed in certain circumstances.BLM, Notice of Intent To Amend the Resource Management Plan for the Rock Springs Field Office, Wyoming, 90 FR 47815, Oct. 2, 2025, FR Doc. 2025-19198, read Oct 18, 2026
Notice of intent October 2, 2025. Scoping comments closed November 3, 2025. We found no later notice for it in the Federal Register when we read it on October 18, 2026. The plan on BLM's ePlanning.
The line
The rights of way
2 rights of way sit inside the line. BLM files 2 under non-energy facilities.
- WYOMING STATE - FORESTRY DIVISION1right of way
- EDEN VALLEY IRRGTN & DRNG DIST1right of way
Grazing allotments
3 grazing allotments cover part of this line. Their permittees aren't named here yet.
- Prospect Mountain48,233acres
- Allotment USFS-GRZ-10190.0104916,730acres
- Big Sandy Ranch1,986acres
The nearest areas
- South Wind River ACECWyoming · 281,188 acres · 58 oil and gas leases, 33 rights of way, 18 grazing allotments covering part of it12miles
- South Pass Historic Landscape ACECWyoming · 53,773 acres · at least 3 active mining claims and 2 more BLM lists as Filed, 4 oil and gas leases, 12 rights of way, 14 grazing allotments covering part of it28miles
- Lander Slope ACECWyoming · 90,469 acres · 18 rights of way, 41 grazing allotments covering part of it30miles
- Red Canyon ACECWyoming · 23,962 acres · 7 rights of way, 9 grazing allotments covering part of it32miles
- Oregon Buttes ACECWyoming · 3,441 acres · 2 grazing allotments covering part of it33miles
More from BLM's Wyoming office
Every area BLM's Wyoming office holdsThe proposed rule
A proposed rule, RIN 1004-AF53, would change how BLM drafts every land use plan, and how it designates ACECs like Big Sandy Openings ACEC. The comment window hasn't opened: the proposed rule wasn't in the Federal Register at our last check. The Watch sends one email the day it prints.
The rule's abstract
The purpose of this rulemaking is to establish in regulations an updated process for the approval of the development, revision, amendment, and maintenance of land use plans, as provided for by the Federal Land Policy and Management Act of 1976, for public lands administered by the Bureau of Land Management (BLM). Additionally, this rulemaking will provide clarification of the process the BLM uses for designating Areas of Critical Environmental Concern.Unified Agenda entry for RIN 1004-AF53, Publication ID 2026, reginfo.gov (OMB OIRA), read Oct 18, 2026