Section 106 of the National Historic Preservation Act (NHPA) requires Federal agencies to "take into account" the effects of their actions on "historic properties" -- that is, "districts, sites, buildings, structures, and objects included in or eligible for the National Register of Historic Places." The National Register is a list of known significant historic places in the United States, Puerto Rico, Guam, American Samoa, the Commonwealth of the Northern Marianas, the Federated States of Micronesia, and the Republics of Palau and the Northern Mariana Islands.
Section 106 is implemented by following regulations issued by the Advisory Council on Historic Preservation.
In general, the Section 106 review process involves the following steps:
- Establish whether the action being considered is a Federal undertaking subject to Section 106 review. Virtually any Federal action that has the potential for environmental impacts -- including many that are categorically excluded from substantial NEPA review -- are subject to Section 106.
- Initiate the review process in consultation with the State and/or Tribal Historic Preservation Officer and other stakeholders. Coordinate with other reviews (e.g. NEPA review), plan for public participation, and identify who to consult.
- Conduct scoping to determine what should be done to identify historic properties and determine effects on them.
- Conduct the necessary identification studies and analyses, in consultation with stakeholders. Note that properties that are eligible for the National Register must be identified, as well as those already included in the Register. This may include heretofore entirely unknown properties.
- Consult further about any effects that may be adverse.
- Execute and implement a Memorandum of Agreement (MOA) about how adverse effects will be resolved, or obtain and consider a final comment from the ACHP.