Colorado · Area of Critical Environmental Concern

Top of the World ACEC

BLM found a natural system, a wildlife resource, a cultural value, a scenic value and a natural process here, and its plan calls for special management. BLM's records place at least 6 active mining claims (and 1 more BLM lists as Filed) and 9 rights of way inside the line today, and two grazing allotments cover part of it. It covers 8,741 acres and was designated January 18, 2024, in the 2024 Eastern Colorado RMP. In the plan's name, RMP stands for resource management plan.

Acres8,741

DesignatedJan 18, 20242024 Eastern Colorado RMP

BLM founda natural system, a wildlife resource, a cultural value, a scenic value and a natural process

Inside, at least17claims, rights of way and allotments, and 1 more claim BLM lists as Filed

The line

Mining claim, 1Claimant withheld by BLM, 5Filed, claimant withheld, 1Right of way, 9

Ground: USGS The National Map, topographic tiles. Boundaries: BLM's own, read Oct 20, 2026. 15 marks are where BLM's own maps draw them; 1 claim is placed at the middle of the section its land description names, not at the stakes on the ground. Hover or tap one for its holder. The 2 grazing allotments below aren't marked.

Who holds the claims

At least 7 claims sit inside this line: 6 active and 1 filed and pending, 1 with a holder BLM names and 6 with a claimant BLM withholds under the Privacy Act. BLM lists 6 as Active and 1 as Filed.

Names withheld by BLM (private individuals)6claims
PARK LAKE RESOURCES LLC1claim

BLM's mining rules list designated ACECs among the places where mining that disturbs the surface beyond casual use needs a plan of operations BLM approves. Exploration of five acres or less can go ahead on a notice instead.

The rights of way

9 rights of way sit inside the line. BLM files 5 under other energy facilities and 4 under non-energy facilities.

PUBLIC SERVICE CO OF CO5rights of way
A private individual, name withheld by this site1right of way
Holder not listed by BLM1right of way
CO DEPT OF TRANS1right of way
CHAFFEE COUNTY TELECOM LLC DBA CO CENTRAL TELECOM1right of way

Grazing allotments

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

Allotment USFS-GRZ-10021.01046537,069acres
Allotment USFS-GRZ-10088.0104658,394acres

The nearest areas

More from BLM's Colorado office

Every area BLM's Colorado 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 Top of the World 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 rule Where the rule stands