Synchronizing Section 106 (NHPA) and NEPA Review Processes

Section 106 of the National Historic Preservation Act (NHPA) and the National Environmental Policy Act (NEPA) are two of the principal federal laws intended to protect environmental and cultural resources. Any project conducted with federal funding, or requiring a federal permit, license, or approval, is required to comply with these laws. So, how are they similar? How are they different? How does compliance with these laws impact your project?

History & Purpose of NHPA

  • Originally passed in 1966.
  • The most comprehensive historic preservation law to date.
  • Section 106 of the NHPA requires federal agencies to consider the effects of their undertakings on historic properties.

History & Purpose of NEPA

  • Enacted in 1970.
  • First piece of hallmark environmental legislation passed in the United States.
  • Requires federal agencies to assess the impacts of their proposed actions on the environment, which includes cultural resources.
Figure 1 Section 106 Process

Cultural Resources or Historic Properties – What’s the Difference?

  • “Cultural Resources” is generally used for all types of archaeological, historic, and/or cultural sites.
  • “Historic Properties” has a very specific meaning under the NHPA. They are defined as sites, structures, buildings, districts, or objects listed in or eligible for listing in the National Register of Historic Places (NRHP). These may include resources of traditional, religious, and cultural significance to American Indian Tribes.

How Section 106 (NHPA) and NEPA Can Work Together

  • Although Section 106 (NHPA) and NEPA are independent statutory requirements, the processes for compliance may require similar studies to identify affected resources, and similar levels of tribal consultation and public engagement.
  • Coordinating review under the two laws not only streamlines both compliance processes but is encouraged or required by the regulations.
  • Streamlining leads to efficiencies in time and therefore costs.

Best Practices

  • Synchronize Planning Efforts
    • Don’t forget to start the NHPA process when you start the NEPA process. This should minimize duplication of effort or delays due to missing key steps in each process.
    • NHPA regulations encourage federal agencies to plan their public participation, analysis, and review in such a way that can meet the purposes and requirements of both statutes in a timely and effective manner.
  • Who’s in Charge?
    • Ideally, the same agency should act as lead agency under both NEPA and Section 106 (NHPA).
  • Plans & Studies
    • Developing plans and schedules for cultural resource identification studies, consultation and public engagement, and other requirements common to both Section 106 (NHPA) and NEPA will help in guiding and keeping the process on track.
  • Schedules & Milestones
    • Timetables are unique to each project. Milestones for Section 106 (NHPA) review should also be incorporated into project NEPA permitting timetables.
  • Begin Tribal Consultation Early
    • Meaningful consultation takes time; it is not a check-box exercise.
    • Section 106 (NHPA): Government-to-government tribal consultation is mandatory when the federal action could adversely affect a historic property that is of religious or cultural significance to an Indian Tribe or Native Hawaiian organization.
    • NEPA: tribal consultation is not explicitly required.
    • The Constitution, treaties, other statues, executive orders and policies: agencies are required to consult when an action may affect the interests of a federally recognized Tribe.
  • Meaningful Consultation is Better than Litigation
    • Litigation risks are reduced if there is active, meaningful consultation with Tribes throughout the project.
  • Synchronize Engagement
    • Section 106 of NHPA requires that the lead agency engages and considers the views of the local community throughout the process.
    • NEPA guidelines direct that agencies make an effort to involve the public in developing and finalizing their NEPA procedures.
    • Synchronized, early engagement will lead to more informed development of alternatives, earlier identification of potential significant issues and data gaps.
  • Identify Potential Affected Resources and Properties
    • Define the Area of Potential Effects (APE) for both Section 106 (NHPA) and NEPA analysis. The APE/project study area may change during a project but understanding them early is critical for good planning.
    • Section 106 (NHPA): only impacts to historic properties must be considered, i.e., resources eligible for listing in the National Register of Historic Places (NHRP).
    • NEPA: “cultural resources” may include natural or biological resources that are subject to ceded territory treaty rights to hunt, fish, and/or gather. These resources often have cultural significance to Tribes.
    • The documents for reporting cultural resources under Section 106 (NHPA) and NEPA may be different, but the identification methods are the same and should be synchronized.
  • Impacting Project Design
    • Early consultation and resources identification could contribute to the development of alternatives for the Environmental Impact Statement (EIS) or Environmental Assessment (EA) and foster the development of appropriate NHPA and NEPA mitigation.


In conclusion, the key take-away points are:

  • Begin early to synchronize planning efforts.
  • Begin tribal consultation as early as possible.
  • Synchronize engagement with stakeholders for NEPA and NHPA.
  • Identify cultural resources and historic properties that could potentially be affected.

If you have additional questions about NHPA and NEPA, please don’t hesitate to get in touch.

Anne Ketz

Anne is CEO and Services Director of 106 Group, a consulting company that specializes in cultural heritage planning. Anne has worked with a broad range of stakeholders, including Native Americans, community planners & leaders, and thought leaders to ensure respect for each community’s heritage within the planning process.