Definitions of terms used in the guidance 

A historic property (or historic resource) is defined in the NHPA [54 U.S.C. § 300308] as any “prehistoric or historic district, site, building, structure, or object included in, or eligible for inclusion on, the National Register of Historic Places, including artifacts, records, and material remains related to such a property or resource.” Following National Register Bulletin No. 36, “Guidelines for Evaluating and Registering Archaeological Properties", an archaeological site is “a location that contains the physical evidence of past human behavior that allows for its interpretation.” The term archaeological site refers to those that are eligible for or are listed on the National Register (historic properties) as well as those that do not qualify for the National Register. The commonly used term cultural resource does not have a consistent or legal definition.

The significance of a property refers to its ability to meet one of the four National Register criteria (A-D). According to National Register Bulletin No. 15, “How to Apply the National Register Criteria for Evaluation, “[t]he quality of significance in American history, architecture, archeology, engineering, and culture is present in districts, sites, buildings, structures, and objects that possess integrity of location, design, setting, materials, workmanship, feeling, and association” and that meet one or more of the four criteria (A-D).  Integrity is the ability of the property to convey this significance through physical features and context. Historic properties are significant because they do meet these criteria and have integrity. Pursuant to Section 101(d)(6)(A) of the NHPA, properties of traditional religious and cultural significance to an Indian tribe or NHO may be deemed eligible for listing on the National Register (See “Consulting with Indian Tribes in the Section 106 Review Process".

Indian tribes, NHOs, ethnic or religious groups, communities, professional and other organizations, or the public may ascribe a cultural, historical, or religious value to an archaeological site. The term value here refers to the site’s worth and importance to them and their experience, regardless of whether the site possesses National Register significance. For example, an archaeological site may be of historical or cultural value to the Mormons, or to an African-American community (See the African Burial Ground Sucess Story), or to the Order Sons of Italy in America, with or without its meeting the criteria for listing in the National Register.

Mitigation is a way to remedy or offset an adverse effect or a change in a historic property’s qualifying characteristics in such a way as to diminish its integrity. Treatment is the act of mitigating those effects, or how one goes about implementing the mitigation measure(s) agreed upon in consultation. Thus, a mitigation plan for the undertaking may contain several treatment plans, one for each property being adversely affected. Data recovery is a common mitigation measure that, through implementation of a treatment plan, retrieves the important information present within an archaeological site that makes it eligible before the site’s integrity is compromised or destroyed.