An area of critical environmental concern (ACEC) is defined in the Federal Land Policy and Management Act (Public Law 94-579, Section 103(a)) as an area within the public lands where special management attention is required to protect and prevent irreparable damage to important historic, cultural, or scenic values; fish and wildlife resources or other natural systems or processes; or to protect life and safety from natural hazards. BLM prepared regulations for implementing the ACEC provisions of FLPMA. These regulations are found at 43 CFR 1610.7-2(b).

To be eligible for designation as an ACEC, an area must meet the relevance and importance criteria described in 43 Code of Federal Regulations (CFR) 1610.7-2 and BLM Manual 1613, Areas of Critical Environmental Concern. An analysis of the existing ACECs and ACECs nominated through the scoping process for the RMP revision can be found in Appendix B.

Restrictions that arise from an ACEC designation are determined when the designation is made and are designed to protect the values or serve the purposes for which the designation was made. In addition, ACECs are protected by the provisions of 43 CFR 3809.1-4(b) (3), which requires an approved plan of operations for activities (except casual use) under mining laws.