Colorado · Area of Critical Environmental Concern
Cumbres and Toltec Scenic Railroad Corridor ACEC
BLM found a scenic value and a historic value here, and its plan calls for special management. BLM's records place no claim, lease or right of way inside the line today, and four grazing allotments cover part of it. It covers 3,904 acres and was designated December 18, 1991, in the 1991 San Luis RMP. 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
Ground: USGS The National Map, topographic tiles. Boundaries: BLM's own, read Oct 20, 2026. The 4 grazing allotments below aren't marked.Grazing allotments
4 grazing allotments cover part of this line. Their permittees aren't named here yet.
- Allotment USFS-GRZ-10223.01035359,333acres
- Llano5,940acres
- Narrow Gauge Comm.5,341acres
- Railroad5,129acres
The nearest areas
- Los Mogotes ACECColorado · 33,447 acres · 2 rights of way, 10 grazing allotments covering part of it7miles
- Ra Jadero Canyon ACECColorado · 3,652 acres · 3 grazing allotments covering part of it16miles
- San Luis Hills ACECColorado · 36,472 acres · at least 3 active mining claims and 79 more BLM lists as Filed, 4 rights of way, 9 grazing allotments covering part of it18miles
- Rio Grande River Corridor ACECColorado · 5,357 acres · at least 1 mining claim BLM lists as Filed, 1 right of way, 6 grazing allotments covering part of it19miles
- Taos PlateauNew Mexico · 288,234 acres · at least 6 active mining claims, 26 rights of way, 74 grazing allotments covering part of it26miles
Next to it
Taos Plateau Area of Critical Environmental Concern touches the line.
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 Cumbres and Toltec Scenic Railroad Corridor 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