State and Tribal Historic Preservation Officers (SHPOs and THPOs) play important roles in the review of impacts on historic properties (places included in or eligible for inclusion in the National Register of Historic Places) under Section 106 of the National Historic Preservation Act and the regulations of the Advisory Council on Historic Preservation. They are also usually recognized by agencies under NEPA as agencies with special expertise in historic preservation, and sometimes in other aspects of cultural resource management. As a result, they often review NEPA documents and participate in NEPA analyses.
Agencies sometimes make the mistake of thinking that NEPA or Section 106 require them to get SHPO or THPO "clearance" for their projects. This is not true, and places unreasonable burdens on the SHPOs and THPOs. In fact, SHPOs and THPOs must be consulted about possible effects on historic properties (including properties that may not currently be identified), but they are not responsible for identifying properties or impacts, nor for giving an agency's project "clearance." Furthermore, they are not the only ones that must be consulted; all other stakeholders, among others, are also legitimate consulting parties.
The roles of SHPOs and THPOs are set forth in the regulations implementing Section 106 of NHPA, and in other guidance available from the ACHP and National Park Service.