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    National Historic Landmark Nomination Process: Glossary

    Please click on any term below to go to its definition.


    Criteria & historic context

    Historic integrity


    Resource types

    Archeological properties

    Other terms


    Property description

    Sources & citations



    Criteria and historic context

    Terms covered in this section: criteria, historic context, NHL themes.

    Criteria: The National Historic Landmarks Program uses six different criteria when evaluating historic properties. For a discussion of the six different criteria, see [link]. Top

    Historic context: A historic context provides the political, social, cultural, and economic background for a particular idea, event, movement, or individual. Historians place historic events within a "historic context" to understand the meaning of an event or a property within a specific culture and/or time period. Placing an event in its context enables historians to better understand if an event was unique or typical of the period, and/or how it may have impacted a culture or period. In a National Historic Landmark nomination, the historic context enables us to determine if the property being nominated is the best, or among the best, illustration(s) of a historic event or movement. The historic context also enables us to understand the role the property played in American history overall. Top

    NHL themes: A theme is a broad pattern in American history. These themes can be used to explain a property's national significance in an NHL nomination. The NHL Program has conducted theme studies on a variety of topics. For a full list, please consult our theme studies page. Top


    Historic integrity

    Historic integrity is the ability of a property to convey its historical associations or attributes. While the NHL and National Register of Historic Places (NR) programs use the same seven aspects of integrity to evaluate properties (location, setting, design, materials, workmanship, feeling, and association) NHLs must retain them to a higher degree than required for NR listing. If the resource has been more than modestly modified or deteriorated since its period of national significance, it may meet the NR threshold for integrity, but not the higher NHL standard.

    Location: Location is the place where the historic property was constructed or the place where the historic event occurred. The actual location of a historic property, complemented by its setting, is particularly important in recapturing the sense of historic events and persons. Top

    Setting: Setting is the physical environment of a historic property. It refers to the historic character of the place in which the property played its historical role. It involves how, not just where, the property is situated and its historical relationship to surrounding features and open space. The physical features that constitute the historic setting of a historic property can be either natural or manmade and include such elements as topographic features, vegetation, simple manmade paths or fences, and the relationships between buildings and other features or open spaces. Top

    Design: Design is the combination of elements that create the historic form, plan, space, structure, and style of a property. This includes such elements as organization of space, proportion, scale, technology, ornamentation, and materials. Design can also apply to districts and to the historic way in which the buildings, sites, or structures are related. Examples include spatial relationships between major features; visual rhythms in a streetscape or landscape plantings; the layout and materials of walkways and roads; and the relationship of other features, such as statues, water fountains, and archeological sites. Top

    Materials: Materials are the physical elements that were combined or deposited during a particular period of time and in a particular pattern or configuration to form a historic property. If the property has been rehabilitated, the historic materials and significant features must have been preserved. The property must also be an actual historic resource, not a re-creation; a property whose historic features have been lost and then reconstructed is usually not eligible. Top

    Workmanship: Workmanship is the physical evidence of the crafts of a particular culture or people during any given period in history. It is the evidence of artisans' labor and skill in constructing or altering a building, structure, object, or site. It may be expressed in vernacular methods of construction and plain finishes or in highly sophisticated configurations and ornamental detailing. Examples of workmanship in historic buildings include tooling, carving, painting, graining, turning, and joinery. Examples of workmanship in precontact contexts include Paleo-Indian Clovis points, Archaic period beveled adzes, Hopewellian worked bone pendants, and Iroquoian effigy pipes. Top

    Feeling: Feeling is a property's expression of the aesthetic or historic sense of a particular period of time. It results from the presence of physical features that, taken together, convey the property's historic character. For example, a rural historic district which retains its original design, materials, workmanship, and setting will relate the feeling of agricultural life in the nineteenth century. Top

    Association: Association is the direct link between an important historic event or person and a historic property. A property retains association if it is the place where the event or activity occurred and is sufficiently intact to convey that relationship to an observer. Therefore, a property where a nationally significant person carried out the action or work for which they are nationally significant is preferable to the place where they returned to only sleep, eat, or spend their leisure time. Like feeling, association requires the presence of physical features that convey a property's historic character. Top



    Terms covered in this section: national significance, period of significance, level of significance.

    National significance: Nationally significant properties tell important stories that have meaning for all Americans, regardless of where they live. A nationally significant property may be:

    • the site of an event that had a significant impact on American history overall (i.e. a turning point in American history)
    • a property directly associated with the productive career of an important individual in American history
    • a site which provides an outstanding illustration of a broad theme in American history
    • the best example of an architectural style or significant development in engineering (i.e. the masterwork of a leading architect or an engineering project that pioneered new techniques), or
    • a site which may yield information which will shape and/or alter the field of archeology. Top

    Period of significance: The period of (national) significance is the period when the historic events associated with a proposed National Historic Landmark occurred. This period must reflect the dates associated with the property being nominated. A period of significance may be thousands of years (in the case of an archeological property), several years, or even a few days, depending on the duration of the event. Top

    Level of significance: The National Park Service assesses properties according to three different levels of significance. A property may be locally significant (have played a role in local events and/or a local community), significant at the state level (have played a role in the history of a specific state), or nationally significant (have played a role in the history of the nation overall). Properties listed in the National Register of Historic Places may be locally significant, significant at the state level, or nationally significant, while National Historic Landmarks must be nationally significant. Top


    Resource types

    Terms covered in this section: building, site, structure, object, district.

    Building: A building is a construction created to shelter any form of human activity. "Building" may also be used to refer to a historically and functionally related unit, such as a courthouse and jail, or a house and barn.

    Examples of buildings include houses, barns, garages, churches, hotels, or similar constructions. The Frick Collection and Frick Art Reference Library in New York, seen below, is a building:

    Frick interior - light green carpet & skylight

    The Frick Collection and Frick Art Reference Library in New York comprise an institution that is considered one of the great legacies of the first period of major art collecting in the United States and one of the defining activities of the Gilded Age elite. Frick's vast fortune, knowledge of the arts and architecture—nurtured and bolstered by a cadre of expert advisors, and desire to create a monument of the most personal sort, resulted in a museum and institution with few rivals. It is one of the best examples of the (art) house museum subset within that type in this country. Its transition from private house museum to publicly accessible institution, whose core mission was retention of the character established by Frick, required an expansion program so expertly conceived by John Russell Pope, that the earlier and later portions read as a seamless whole. Pope's additions, constructed between 1931 and 1935, included a much-expanded Frick Art Reference Library, which has been an integral aspect of the institution since its 1920 founding by daughter Helen Clay Frick (1888-1984). The Frick Collection and Frick Art Reference Library Building maintain an uncommon degree of physical integrity and convey the character defining features that underpin its national significance both for its architecture and as a cultural institution. Top

    Site: A site is the location of a significant event where a historic occupation or activity occurred. It may be the site of a building or structure which is no longer standing or which exists only as a ruin. A site may also include a standing building, if the location itself possesses historic, cultural, or archeological value regardless of the value of any existing structure.

    Examples of sites include rock shelters, village sites, hunting and fishing sites, ceremonial sites, petroglyphs, rock carvings, gardens, grounds, battlefields, ruins of historic buildings and structures, habitation sites, funerary sites, campsites, sites of treaty signings, trails, areas of land, shipwrecks, cemeteries, designed landscapes, and natural features, such as springs and rock formations. The USS Monitor in North Carolina and Mount Auburn Cemetery in Massachusetts, seen below, are sites:

    Autumn photo of tombstones with a red-leafed tree in foreground

    Photograph by Friends of Mount Auburn via Flickr

    With its stone monuments seated within a tranquil retreat of grass and flowers, the Mount Auburn Cemetery exemplifies the characteristics of rural cemeteries. Mount Auburn initiated the great age of American cemetery-building and influenced the design of public parks, monuments, and suburbs. This site provides insights into nineteenth-century attitudes about death and had a significant influence on the design of other cemeteries. Top


    The USS Monitor (1862), famous for her Civil War battle with CSS Merrimac, was the prototype of a class of ironclad, turreted warships which significantly altered both naval technology and marine architecture in the nineteenth century. Designed by Swedish engineer John Ericsson, the vessel contained all of the nascent innovations which helped to revolutionize warfare at sea.














    Structure: The term "structure" is used to distinguish from buildings those constructions made usually for purposes other than creating human shelter.

    Examples of structures include bridges, tunnels, gold dredges, firetowers, canals, turbines, dams, power plants, corncribs, silos, roadways, shot towers, windmills, grain elevators, kilns, mounds, cairns, palisade fortifications, earthworks, railroad grades, systems of roadways and paths, boats and ships, railroad locomotives and cars, telescopes, carousels, bandstands, gazebos, and aircraft. The Highland Park Dentzel Carousel, seen below, is a structure:

    Closeup of carousel animals, including a tiger and horse

    Photograph by marcia-s via Flickr

    This wooden carousel (ca.1892-99) is likely the oldest of the three earliest Dentzel menagerie carousels that remain virtually intact. Over 100 of these carousels were produced by the Dentzel Company of Philadelphia, founded in the mid-nineteenth century by the son of a German carousel crafter. It is the only one of the three still in an historic "shelter" or carousel house. Top

    Object: The term "object" is used to distinguish from buildings and structures those constructions that are primarily artistic in nature or are relatively small in scale and simply constructed. Although it may be, by nature or design, movable, an object is associated with a specific setting or environment.

    Examples of objects include sculpture, monuments, boundary markers, statuary, and fountains. The Lily Pool in Illinois, seen below, is an example of an object:

    Color photo of lily pool

    Photograph by Eric Allix Rogers via Flickr

    The Lily Pool is an exquisite hidden garden in Chicago's Lincoln Park that symbolically celebrates the natural and pre-history of the Midwest. In recent years, the Chicago Park District renamed this site the Alfred Caldwell Lily Pool, in tribute to its talented creator. Considered the last great Prairie style landscape architect of the twentieth century, Alfred Caldwell (1903- 1998) was also an accomplished planner, architect, teacher, poet and essayist. Included in the lily pool is an elaborate waterfall. Top

    District: A district possesses a significant concentration, linkage, or continuity of sites, buildings, structures, or objects that are historically or aesthetically united by either a plan or physical development.

    Examples of districts include college campuses; central business districts; residential areas; commercial areas; large forts; industrial complexes; civic centers; rural villages; canal systems; collections of habitation and limited activity sites; irrigation systems; large farms, ranches, estates, or plantations; transportation networks; and large landscaped parks. The Tombstone Historic District in Arizona, seen below, is an example of a district:

    Street scene of old building facades in Tombstone

    Photograph by Gabriel Millos via Flickr

    Tombstone is one of the best-preserved specimens of the rugged frontier town of the 1870s and '80s. Site of one of the West's richest silver strikes and the "gunfight at the OK Corral," Tombstone epitomizes the legendary reputation of the "Wild West" and lawlessness of the nineteenth century mining camps. Top


    Archeological properties

    Terms covered in this section: integrity, research agenda, ecofacts, type site.

    Integrity requirements for nationally significant archeological properties: Archeological properties must have an appropriate level of physical remains in considering a property's ability to yield the nationally significant information described in a research agenda . Properties that have been partly excavated or otherwise disturbed and that are being considered for their potential to yield additional nationally significant information must be shown to retain that potential in their remaining portions. Archeological properties eligible for NHL designation must have enough archeological integrity to answer nationally significant questions. They need not address the seven aspects of integrity.

    Properties that have yielded important information in the past and that no longer retain additional research potential (such as completely excavated archeological sites) must be assessed as historic sites under Criterion 1. These sites must be significant for the national importance of the data gained and the impact of the property's role in the history of the development of anthropology/archeology or other relevant disciplines. Amalik Bay in Alaska, seen below, is an archeological site:

    Green grass, blue water, and mountain at Amalik Bay

    Amalik Bay was a gateway for the widespread exchange of ideas and technological innovations, including ground-slate tools and Norton-style pottery, hallmarks in the development of coastal Eskimo economies across the far northern reaches of the continent.The Amalik Bay sites, located in a position between the Bristol Bay side of the Alaska Peninsula to the northwest (linguistically Yupik Eskimo) and Kodiak Island (Alutiiq Eskimo) to the southeast, possess the potential to shed light on provocative questions concerning Alutiiq ethnogenesis. Top

    Research agenda: A research agenda is a strategy for archeological problem solving that clarifies the goals and guides the procedures of a research project. This explanatory framework, or research design, identifies the important research questions that an archeological property or group of properties can address, based on the cultural and archeological context, the data sets, and the integrity of those data sets at a property or properties. A research design also includes information on the methods used to gather the data. Top

    Ecofacts: Ecofacts are ecological evidence (e.g. pollens remaining from plants that were in the area when human activities occurred) that are of interest to archeologists. Ecofacts, along with artifacts, are often collected by archeologists because they can provide important information about human activity and culture. Top

    Type site: In archeology, a type site is a site that is considered the model of a particular archeological culture. A type site contains artifacts in an assemblage that are typical of that culture. Type sites are often the first or foundational site discovered about the culture they represent. Top


    Other terms

    Terms covered in this section: easement, rehabilitation, buffer zone, National Register of Historic Places.

    Easement: Historic preservation easements are used to protect historic buildings, landscapes, battlefields, traditional cultural places, or archeological sites. A preservation easement is a voluntary legal agreement that provides assurance to the owner of a historic or cultural property that the property's historic character will be preserved through subsequent ownership. Under the terms of an easement, a property owner grants a portion of, or interest in, his/her property rights to an organization whose mission includes historic preservation. Once recorded, an easement becomes part of the property's chain of title and usually "runs with the land" in perpetuity, thus binding not only the owner who grants the easement but all future owners as well. The owner may obtain substantial tax benefits. Top

    Rehabilitation: The Secretary of the Interior's Standards for Rehabilitation are ten basic principles created to help preserve the distinctive character of a historic building and its site, while allowing for reasonable change to meet new needs. The Standards (which are based on 36 CFR § 67) apply to historic buildings of all periods, styles, types, materials, and sizes. They apply to both the exterior and the interior of historic buildings. The Standards also encompass related landscape features and the building's site and environment as well as attached, adjacent, or related new construction. Top

    Rehabilitation projects for commercial properties must meet the Standards, as interpreted by the National Park Service, to qualify as "certified rehabilitations" eligible for the 20 percent rehabilitation tax credit. The Standards are applied to projects in a reasonable manner taking into consideration economic and technical feasibility. Top

    Buffer zone: A buffer zone is acreage (land, water, etc.) at the edge of a National Historic Landmark that does not directly contribute to the significance of the property (i.e. which did not play a role in the events or activity associated with the National Historic Landmark) but which is included in a National Historic Landmark boundary. The NHL Program does not allow buffer zones in National Historic Landmarks. Top

    National Register of Historic Places: The National Register of Historic Places is the nation's official list of historic properties worthy of preservation. To learn more, please visit the National Register of Historic Places's website. Top


    Property description

    Terms covered in this section: contributing resources, noncontributing resources, identification of principle rooms, materials used, map/site plan, crosshatching, numbering, coding.

    Contributing resources: Contributing resources are the buildings, objects, sites, and structures that played a role or, more simply, existed at the time the event(s) associated with the proposed National Historic Landmark occurred. Top

    Noncontributing resources: Noncontributing resources are the buildings, objects, sites, and structures that did not exist at the time the event(s) associated with the proposed National Historic Landmark occurred or have lost integrity from that historic period. Top

    Identification of principle rooms: The importance of describing room arrangements also applies to residential architecture. A kitchen might be in the basement, or in an attached ell. There may be servants' rooms in the attic level, or children's rooms. Each room need not be described where repetition is involved, such as with bedrooms. Pay close attention to those rooms associated with the national significance of the property. For example, a room used by a nationally significant attorney as a home office is more important than his bedroom. Top

    Materials used: What type of alterations and materials should be identified in terms of NHL designation? The identification of a slate roof rather than synthetic imitation slate, or the use of stucco, rather than a twentieth-century synthetic imitation stucco, is a question of integrity. The identification of the use of a local sandstone, or an early use of glazed terra cotta, contributes to a better understanding of the significance of the property. Top

    Map/site plan: A map and/or site plan should include: the boundaries of the property, carefully delineated; the names of streets or highway numbers, including those bordering the property; a north arrow and approximate scale, if done to scale; names or numbers of parcels that correspond to the description of the resources in Section 7; contributing resources, (these should be numbered and the numbering should correspond to the listing of buildings, sites, structures and objects listed in Section 7); noncontributing resources (these should be numbered and the numbering should correspond to the listing of buildings, sites, structures, and objects listed in Section 7); and other natural features or land uses covering substantial acreage or having historical significance such as forests, fields, rivers, lakes, etc.

    Archeological sites and districts should also include the location and extent of disturbances, including previous excavations; the location of specific significant features and artifact loci; and the distribution of sites if it is an archeological district. Top

    Crosshatching: Crosshatching is shading which has two or more intersecting parallel lines. The map of the Borax Lake Site in California, seen below, uses crosshatching:.

    B&W map with crosshatching


    Numbering: Numbers and a map key may be used to indicate buildings, structures, and objects on a map. The map of the Skidmore/Old Town Historic District in Oregon, seen below, uses numbering:

    Map of Old Town in Portland, Oregon with a numbered key


     Coding: Coding entails using shading to differentiate between buildings, structures, and objects on a map. The map of the Breakthrough at Petersburg Battlefield in Virginia, seen below, uses coding:

    B&W map of Peterburgh Battle showing troop movements



    Sources & citations

    Terms covered in this section: primary sources, secondary sources, footnoted citations, block quotation, bibliography, evaluating internet sources.

    Primary sources were either created during the time period being studied or were created at a later date by a participant in the events being studied (as in the case of memoirs).  These sources reflect the individual viewpoint of a participant or observer.  Examples of primary sources include: letters, diaries, records kept by an organization to document its day-to-day activities, and contemporary newspapers.

    Primary sources can also be graphic, such as historical photographs, blueprints, renderings, sketches, maps, and site plans. Information obtained from graphic sources should be cited in the same way as written sources. Top

    Secondary sources interpret or analyze an historical event or phenomenon.  These sources are generally written by historians or scholars who use primary sources to interpret an historical event or phenomenon.  Examples of secondary sources include: scholarly or popular books as well as articles written by historians or scholars, reference books such as encyclopedias, textbooks, and documentary films.

    Sometimes scholars are in disagreement over the interpretation of an event. Conduct a broad sample of the historical literature to determine the general consensus of scholars.

    When using secondary sources, please be sure to use the most recent works. Top

    Footnoted citations: Footnotes comment on or cite a reference from another text. These appear at the bottom of the page. Top

    Block quotation: A block quotation is a long quotation (two or more paragraphs) that is set off from the rest of the text. The NHL Program prefers that block quotations be used sparingly in a nomination. Top

    Bibliography: A bibliography is a list of the works (books, articles, websites, oral history interviews, etc.) used in a National Historic Landmark nomination or any scholarly piece of work. Top

    Evaluating internet sources: When looking at websites (and other sources), bear these four factors in mind.

    • Authority: What institution produced this site? And why? Check the website domain name. You can generally trust .edu and .gov domains. For other domain names you may need to look more closely and ask the questions listed here.
    • Accuracy: Who wrote the website? What was the purpose of the website and why was it created? Is the individual who wrote this website qualified to do so? Does the author list his or her qualifications?
    • Objectivity: What factors have shaped the author's opinions? What are the goals and objectives of the website? Is it intended simply to promote the organization or is it an unbiased assessment of an historical event or property?
    • Currency: When was the website created? Has it been updated and, if so, when? Are the sources and links cited current?

    Remember: If part of the website is behind a pay wall or if you have limited access to the website because it requires a specific type of software which you do not possess, you are only getting part of the source material.

    Using Wikipedia: Because scholars have noted multiple errors in Wikipedia entries, you should avoid using this source. Top