A Brief Explanation of NEPA and Section 106 Reviews

Section 106 of the National Historic Preservation Act (NHPA) and the National Environmental Policy Act (NEPA) are two separate laws that require federal agencies to “stop, look, and listen” before making decisions impacting historic properties and the human environment. Section 106 and NEPA have different parameters for what type of action may trigger review and what type of resources are afforded consideration in each review. Section 106 review concerns effects only to historic properties, while NEPA encompasses consideration of impacts to a wider range of resources within the human environment.

Section 106 of the NHPA requires federal agencies to consider the effect of undertakings they conduct, license, approve, or fund on historic properties and provide the Advisory Council on Historic Preservation (ACHP) a reasonable opportunity to comment before making decisions. Using the Section 106 process, agencies identify historic properties, assess effects on historic properties, consider alternatives to avoid, minimize, or mitigate any adverse effects, and document their resolution. Agencies are required to facilitate a stakeholder engagement process known as consultation—discussing and considering the views of consulting parties, including State Historic Preservation Officers (SHPOs) and/or Tribal Historic Preservation Officers (THPOs), Indian Tribes, Native Hawaiian Organizations, local governments, applicants, and others, while also providing opportunities for public input. The ACHP, an independent federal agency established by the NHPA, oversees the implementation of the Section 106 process, issues its implementing regulations (36 CFR Part 800), and may participate in consultation to resolve adverse effects to historic properties.

NEPA, as amended by the Fiscal Responsibility Act of 2023 (FRA), P.L. 188-5, establishes the national environmental policy of the federal government to use all practicable means and measures to foster and promote the general welfare, create and maintain conditions under which humans and nature can exist in productive harmony, and fulfill the social, economic, and other requirements of present and future generations of Americans. NEPA contains procedural requirements to conduct the national environmental policy. Specifically, NEPA requires federal agencies to provide a detailed statement on proposals for major federal actions significantly affecting the quality of the human environment. The purpose and function of NEPA is satisfied if federal agencies have considered relevant environmental information, and the public has been informed regarding the decision-making process. NEPA does not mandate particular results or substantive outcomes. Rather, NEPA requires federal agencies to consider the environmental effects of proposed actions as part of agencies’ decision-making processes.

NEPA established the Council on Environmental Quality (CEQ) within the Executive Office of the President. CEQ assists and advises the President on certain environmental matters and the implementation of the national environmental policy. NEPA directs all federal agencies to consult with CEQ while identifying and developing methods and procedures to ensure that unquantified environmental amenities and values may be given appropriate consideration in the decision-making process along with economic and technical considerations. NEPA further requires federal agencies to review their authorities, regulations, policies, and procedures and propose measures to align them with the intent, purposes, and procedures of NEPA.

Integration of NEPA and Section 106 Reviews

Federal agencies’ statutory obligations under NEPA and NHPA are independent, but integrating the processes creates efficiencies, promotes transparency and accountability, and supports a broad discussion of effects on the human environment. In March 2013, CEQ and the ACHP developed a Handbook to promote better integration of the two review processes. While the relationship between NEPA and Section 106 reviews remains fundamentally the same as provided in the Handbook, the Handbook will be revised to align with recent changes related to NEPA.

Section 106 review must be complete prior to issuance of a federal decision, so that a broad range of alternatives may be considered during the planning process. Because the information gathering and consultation done in the Section 106 review should inform the NEPA review, and vice versa, the timing of both reviews should be coordinated. For example, a finding of adverse effect under Section 106 may help an agency determine whether it can use a categorical exclusion to avoid NEPA requirements for an environmental assessment or environmental impact statement for a particular action.

Integrating the NEPA and Section 106 processes makes sense because: the historic properties of concern in Section 106 are one type of resource in the human environment considered in NEPA; both processes are triggered by federal funding, permits, licenses, or other approvals and share goals of providing transparency and allowing for public involvement; both processes should be initiated early in project planning when a broad range of alternatives can be considered; and, completion of both processes is needed for agencies to make a final decision regarding an action or undertaking. In addition, federal agencies are encouraged to combine public involvement efforts for the two reviews to avoid duplication of effort and to maximize opportunities for public and consulting party involvement.

Recent updates

The CEQ previously promulgated regulations implementing NEPA in response to Executive Order (E.O.) 11991, Relating to the Protection and Enhancement of Environmental Quality, issued by President Carter on May 24, 1977, which also required federal agencies to comply with CEQ’s implementing regulations. On January 20, 2025, President Trump signed E.O. 14154, Unleashing American Energy, which revoked E.O. 11991 and directed CEQ to issue guidance to agencies on implementing NEPA and to propose rescinding CEQ’s NEPA regulations. E.O. 14154 further instructed CEQ to coordinate the revision of agencies’ NEPA implementing regulations.

Consistent with E.O. 14154, federal agencies must revise or establish their NEPA implementing procedures to expedite permitting approvals and for consistency with NEPA, as amended by the FRA. CEQ has issued guidance to assist federal agencies with implementation of NEPA while these revisions are ongoing.