National Register boundaries, therefore, have legal implications that can affect the property's future. Private property owners can do anything they wish with their property, provided no Federal license, permit, or funding is involved. To be in compliance with the act, Federal agencies must identify and evaluate National Register eligibility of properties within the area of potential effect and evaluate the effect of the undertaking on eligible properties. The area of potential effect may include historic properties that are well beyond the limits of the undertaking. For example, a Federal undertaking outside of the defined boundaries of a rural traditional cultural property or an urban historic district can have visual, economic, traffic, and social effects on the setting, feeling, and association of the eligible resources.
Large properties present special problems.
For example, an undertaking in a narrow corridor, such as a pipeline, may affect part of a large archeological site, traditional cultural property, or rural historic district. Such properties may extend far beyond the area of potential effect or access may be denied in areas beyond the undertaking. It is always best to consider the entire eligible property, but it may not be possible or practical to define the full extent of the property. Consider all available information and select boundaries on the basis of the best information available. When defining boundaries of large resources extending beyond the area of potential effect, it is advisable to consult the State historic preservation office.