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Wyoming · Area of Critical Environmental Concern

Little Mountain ACEC

One of 2 areas BLM's Wyoming office names Little Mountain ACEC; this one is 115,571 acres. All of them. BLM found a wildlife resource, a cultural value, a scenic value, a historic value and a fish resource here, and its plan calls for special management. BLM's records place 1 oil and gas lease and 20 rights of way inside the line today, and ten grazing allotments cover part of it. It covers 115,571 acres and was designated December 22, 2024, in the Rock Springs Resource Management Plan.

Acres115,571
DesignatedDec 22, 2024Rock Springs Resource Management Plan
BLM founda wildlife resource, a cultural value, a scenic value, a historic value and a fish resourceand found it important
Inside31leases, rights of way and allotments

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

Little Mountain ACEC
Right of way, 20
Ground: USGS The National Map, topographic tiles. Boundaries: BLM's own, read Oct 20, 2026. 20 marks are where BLM's own maps draw them. Hover or tap one for its holder. The lease and 10 grazing allotments below aren't marked.

The rights of way

20 rights of way sit inside the line. BLM files 12 under non-energy facilities, 3 under oil & gas facilities, 2 under interstate energy facilities, 2 under other energy facilities and 1 under water.

  • WYOMING DEPARTMENT OF TRANSPORTATION4rights of way
  • SWEETWATER COUNTY (Wyoming)3rights of way
  • PACIFICORP2rights of way
  • SIMPLOT PHOSPHATES LLC2rights of way
  • RAVEN RIDGE PIPELINE COMPANY1right of way

The oil and gas leases

1 active oil and gas lease sits inside the line. 1 of it took effect before the area was designated on December 22, 2024.

  • DOMINION ENERGY QUESTAR PIPELINE LLC1lease

Grazing allotments

10 grazing allotments cover part of this line. Their permittees aren't named here yet.

  • Rock Springs2,185,958acres
  • Sugarloaf77,919acres
  • Pine Mountain74,538acres
  • Mellor Mountain69,709acres
  • Red Creek69,104acres

The nearest areas

Next to it

Red Creek Watershed Area of Critical Environmental Concern touches the line.

More from BLM's Wyoming office

Every area BLM's Wyoming office holds

The proposed rule

A proposed rule, RIN 1004-AF53, would change how BLM drafts every land use plan, and how it designates ACECs like Little Mountain 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

Watch the ruleWhere the rule stands