Colorado · Area of Critical Environmental Concern
Ancestral Puebloan ACEC
BLM found a natural system and a cultural value here, and its plan calls for special management. BLM's records place 2 rights of way inside the line today, and two grazing allotments cover part of it. It covers 801 acres and was designated January 29, 2020, in the 2020 TRFO ACEC RMP Amendment. In the plan's name, TRFO stands for BLM's Tres Rios Field Office and RMP 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
2 rights of way sit inside the line. BLM files 1 under other energy facilities and 1 under non-energy facilities.
- EMPIRE ELEC ASSN INC1right of way
- A private individual, name withheld by this site1right of way
Grazing allotments
2 grazing allotments cover part of this line. Their permittees aren't named here yet.
- Mud Springs953acres
- Lower Aztec Canyon290acres
The nearest areas
- Sand Canyon ACEC/RNAColorado · 1,777 acres · 2 oil and gas leases8miles
- Mesa Verde Escarpment ACECColorado · 7,420 acres · 6 rights of way, 3 grazing allotments covering part of it8miles
- Cannonball Mesa ACEC/RNAColorado · 2,436 acres · 6 oil and gas leases, 1 right of way, 4 grazing allotments covering part of it15miles
- McElmo ACEC/RNAColorado · 4,105 acres · 3 oil and gas leases, 1 right of way, 2 grazing allotments covering part of it20miles
- HovenweepUtah · 2,439 acres · 1 oil and gas lease, 1 right of way, 3 grazing allotments covering part of it23miles
More from BLM's Colorado office
Every area BLM's Colorado 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 Ancestral Puebloan 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