Montana · Area of Critical Environmental Concern
Centennial Mountains
BLM found a wildlife resource, a scenic value and a natural process here, and its plan calls for special management. BLM's records place 10 rights of way inside the line today, and 17 grazing allotments cover part of it. It covers 40,782 acres and was designated February 7, 2006, in the Dillon RMP (2006). In the plan's name, RMP stands for 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.
The line
The rights of way
10 rights of way sit inside the line. BLM files 10 under non-energy facilities.
- MT STATE OF2rights of way
- DILLON FIELD OFFICE1right of way
- J R SIMPLOT CO1right of way
- BLM DILLON FIELD OFFICE1right of way
- BUTTE FIELD OFFICE1right of way
- NRCS1right of way
- Montana/Dakotas State Office1right of way
- UK HOLDINGS LTD1right of way
- Holder not listed by BLM1right of way
Grazing allotments
17 grazing allotments cover part of this line. Their permittees aren't named here yet.
- PRICE CREEK19,945acres
- Allotment USFS-GRZ-10865.01049517,878acres
- SHAMBO UNIT14,042acres
- Allotment USFS-GRZ-10875.01049511,903acres
- PEET CREEK7,819acres
- DUFF CREEK5,813acres
- UNAVAILABLE_CENT5,590acres
- Allotment USFS-GRZ-10838.0104954,587acres
- Allotment USFS-GRZ-10186.0103493,911acres
- Allotment USFS-GRZ-10864.0104953,907acres
- Allotment USFS-GRZ-10900.0104953,503acres
- Allotment USFS-GRZ-10881.0104953,265acres
- TOM CREEK2,823acres
- UNLEASED_CENT1,882acres
- MORTON INDIVIDUAL746acres
- DAVIS SGC COMMON453acres
- MCCANDLESS BROS364acres
The nearest areas
- Centennial SandhillsMontana/Dakotas · 1,047 acres · 3 grazing allotments covering part of it9miles
- Henrys LakeIdaho · 35,870 acres · 31 rights of way, 12 grazing allotments covering part of it25miles
- St. Anthony Sand Dunes RNAIdaho · 1,824 acres · a grazing allotment covering part of it40miles
- Nine Mile KnollIdaho · 41,641 acres · 10 rights of way, 8 grazing allotments covering part of it41miles
- Blue LakeMontana/Dakotas · 430 acres · 2 grazing allotments covering part of it45miles
More from BLM's Montana/Dakotas office
Every area BLM's Montana/Dakotas 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 Centennial Mountains. 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