The National Environmental Policy Act (NEPA) process begins when a federal agency develops a proposal to take a major federal action. These actions are defined at 40 CFR 1508.1. The environmental review under NEPA can involve three different levels of analysis:

1. Categorical Exclusion determination (CATEX)

2. Environmental Assessment/Finding of No Significant Impact (EA/FONSI)

3. Environmental Impact Statement (EIS)

Section 106 of the National Historic Preservation Act of 1966 (NHPA) requires federal agencies to consider the effects on historic properties of projects they carry out, assist, fund, permit, license, or approve throughout the country. If a federal or federally-assisted project has the potential to affect historic properties, a Section 106 review will take place.

Section 106 gives the ACHP, interested parties, and the public the chance to weigh in on these matters before a final decision is made. This process is an important tool for citizens to lend their voice in protecting and maintaining historic properties in their communities.