Utah · Area of Critical Environmental Concern
Fiftymile Mountain
BLM found a natural system, a cultural value, a scenic value, a natural process and a natural hazard here, and its plan calls for special management. BLM's records place no claim, lease or right of way inside the line today, and five grazing allotments cover part of it. It covers 54,845 acres and has no decision date on BLM's map, and no plan named on it either.
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 5 grazing allotments below aren't marked.
Grazing allotments
5 grazing allotments cover part of this line. Their permittees aren't named here yet.
- Last Chance250,126acres
- Soda70,412acres
- Rock Creek-Mudholes64,885acres
- Fortymile Ridge57,891acres
- Lake22,739acres
The nearest areas
- No Mans MesaUtah · 1,464 acres · 2 grazing allotments covering part of it49miles
- Marble CanyonArizona · 11,500 acres · 1 right of way, 2 grazing allotments covering part of it54miles
- Johnson SpringArizona · 3,445 acres · 7 grazing allotments covering part of it65miles
- North Caineville MesaUtah · 1,972 acres · a grazing allotment covering part of it73miles
- ShinarumpArizona · 3,238 acres · at least 1 active mining claim, 4 grazing allotments covering part of it75miles
More from BLM's Utah office
Every area BLM's Utah 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 Fiftymile 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