Section 106 of the National Historic Preservation Act requires a review of any Federal project that could potentially impact a historic property. There are four steps in the Section 106 compliance process. This page outlines how to complete Step Three of the process. There are similar, separate pages for Step One, Step Two and Step Four. Be sure to check them out!


To complete STEP THREE, answer this question:

Once you know that the undertaking will affect historic properties, then determine the appropriate level of effect. To do this, apply the criteria of adverse effect. Adverse effects on historic properties include but are not limited to:

  • Physical destruction of or damage to all or part of the property;
  • Alteration of a property, including restoration, rehabilitation, repair, maintenance, stabilization, hazardous material remediation and provision of handicapped access that is not consistent with the Secretary’s Standards for the Treatment of Historic Properties (36 CFR §68) and applicable guidelines;
  • Removal of the property from its historic location;
  • Change of the character of the property’s use or of physical features within the property’s setting that contribute to its historic significance;
  • Introduction of visual, atmospheric or audible elements that diminish the integrity of the property’s significant historic features;
  • Neglect of a property which causes its deterioration, except where such neglect and deterioration are recognized qualities of a property of religious and cultural significance to an Indian tribe or Native Hawaiian organization; and
  • Transfer, lease, or sale of a historic property out of Federal ownership or control without adequate and legally enforceable restrictions or conditions to ensure long-term preservation of the property’s historic significance.

In applying the criteria of adverse effects you must consider direct and indirect effects, as well as cumulative effects. Be sure to consider the impacts of an undertaking on all of the characteristics that qualify a historic property for listing in the National Register of Historic Places. For example, an archeological site may be important for its informational potential, but could also be significant for its religious or cultural association with a contemporary Indian tribe, which may affect your determination.

After applying the criteria of adverse effect, determine if your undertaking will have “no adverse effect” or an “adverse effect” on historic properties and resume consultation with appropriate parties (SHPO/THPO, Tribes and Other Consulting Parties).

If you determine…

No Adverse Effect: If you determine that the effects of the proposed undertaking do not meet the criteria of adverse effect (i.e., the undertaking would not adversely affect historic properties), then propose a finding of “no adverse effect,” notify all consulting parties, and provide them with the documentation. The SHPO/THPO has 30 days of receipt to review the finding.


Adverse Effect: If you determine that the effects of the proposed undertaking meet the criteria of adverse effect (i.e., the undertaking would adversely affect historic properties) then propose a finding of “adverse effect” and notify all consulting parties and provide them with the documentation. The SHPO/THPO has 30 days of receipt to review the finding. If you have an Adverse Effect finding, proceed to Step 4.

SHPO Response

Agreement: The agency may proceed after the close of the 30 day review if the SHPO/THPO has agreed with the finding or has not provided a response, and no consulting party has objected.


Disagreement: If, within the 30 day review period, the SHPO/THPO or any consulting party notifies the agency in writing that it disagrees with the finding and specifies the reasons for the disagreement, the agency shall consult with the party to resolve the disagreement, or request the Advisory Council on Historic Preservation (ACHP) to review the finding. The ACHP has 15 days to review the finding and respond with its opinion as to whether the adverse effect criteria have been appropriately applied. The agency shall take into account the opinion of the ACHP in reaching a final decision on the finding.


For either a determination of “no adverse effect” or “adverse effect,” the regulations in 36 CFR §800.11(e) require that specific information be documented and submitted to SHPO/THPO and the consulting parties.

This documentation shall include:

  • A description of the undertaking, specifying the Federal involvement, and its area of potential effects, including photographs, maps, drawings, as necessary;
  • A description of the steps taken to identify historic properties;
  • A description of the affected historic properties, including information on the characteristics that qualify them for the National Register;
  • A description of the undertaking’s effects on historic properties;
  • An explanation of why the criteria of adverse effect were found applicable or inapplicable, including any conditions or future actions to avoid, minimize, or mitigate adverse effects; and
  • Copies or summaries of any views provided by consulting parties and the public. You may use any format you wish to document this information, as long as the required information is effectively conveyed. For the National Park Service, using the assessment of effect (AEF) form (this can be found in PEPC) is a common way to ensure that all the necessary information is included.



Adverse Effect: An adverse effect is when an undertaking may alter any of the characteristics of a historic property that qualify the property for inclusion in the National Register in a manner that would diminish the integrity of the property’s location, design, setting, materials, workmanship, feeling, or association.
Direct Effects: Effects that cause alterations in the character or use of historic properties. For example, ground disturbance or changing a window in a historic building.
Indirect Effects: May include other areas where the undertaking will cause changes in land use, traffic patterns, or other aspects that could affect cultural resources, including visual, atmospheric, or audible changes. For example, introducing an intrusion into a cultural landscape or construction noise in a national cemetery.
Assessment of Effect Form: Typically, the National Park Service uses the Assessment of Effect (AEF) form to ensure that all the necessary information for documenting an assessment of effect is included. The AEF provides a useful checklist to ensure that you have documented all the pertinent information such as the decisions that were reached through interdisciplinary discussions and partnership consultations.
PEPC: Stands for Planning, Environment and Public Comment and is an electronic database provides the National Park Service with information technology tools for efficient park planning and resource compliance, project tracking, and public engagement to support collaboration and informed decision making. The NPS requires that Section 106 compliance is documented in PEPC. An Assessment of Effect form can be found in the PEPC system.


Watch an interview with Jeff Durbin, National Section 106 Compliance Program Manager, as he explains Step Three of the Section 106 Process.

Audio Description Video for Step Three
Step Three Video Transcript

Next Step(s)

If there are no properties that will be adversely affected, submit the AEF to SHPO, THPO, tribes & consulting parties for 30 day review. After 30 days, Section 106 Compliance is complete. If properties will be adversely affected, continue to Step Four of the 106 process.

Write a Review

  1. Rating:

  2. I appreciate the flexibility of the 106 process and the potential diversity of outcomes – that is, the process is a conversation between many stakeholders who care about making good decisions, and not a rote paint-by-numbers sort of thing. Even though it is complex and time-consuming.

  3. To answer the question, yes there are are adverse effects. I would have thought that the use of a product made of modern materials and considered an adverse effect would have made the decision clear cut for either asphalt or wood. interesting and proves these decisions can be difficult.

  4. Rating:

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