California · Area of Critical Environmental Concern
Castle Mountain
BLM found a wildlife resource, a cultural value and a historic value here, and its plan calls for special management. BLM's records place at least 126 active mining claims inside the line today, with 317 more BLM lists as Filed. It covers 3,695 acres and was designated September 14, 2016, in the CDCA Plan, as amended by DRECP. In the plan's name, CDCA stands for California Desert Conservation Area and DRECP for Desert Renewable Energy Conservation 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
Who holds the claims
At least 443 claims sit inside this line: 126 active and 317 filed and pending, 443 with a holder BLM names. BLM lists 317 as Filed and 126 as Active.
- CASTLE MOUNTAIN VENTURE372claims
- VICEROY GOLD CORP71claims
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 nearest areas
- Piute/EldoradoNevada · 323,710 acres · at least 47 active mining claims and 4 more BLM lists as Filed, 43 rights of way12miles
- Crescent TownsiteNevada · 436 acres · nothing placed inside14miles
- Piute-FennerCalifornia · 178,838 acres · at least 4 active mining claims and 1 more BLM lists as Filed, 14 rights of way25miles
- Mountain Pass Dinosaur TrackwayCalifornia · 596 acres · at least 24 active mining claims25miles
- IvanpahCalifornia · 86,428 acres · at least 703 active mining claims and 637 more BLM lists as Filed, 42 rights of way, a grazing allotment covering part of it27miles
More from BLM's California office
Every area BLM's California 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 Castle Mountain. 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