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 [graphic] National Register Bulletin Guidelines for Evaluating and Documenting Historic Aids to Navigation to the National Register of Historic Places

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U.S. Department of the Interior, National Park Service


While basic instructions for completing nominations are found in National Register bulletin: Guidelines for Completing National Register of Historic Places Forms, several sections of the form will require the specialized information provided in the following guidelines. For the purposes of the National Register, single aids to navigation are classified as structures, or, if in ruins, as sites. Sometimes they are parts of districts which include buildings, other structures, or objects.

In the narrative in Section 7, Description, and in Section 8, Statement of Significance, of the registration form, develop fully and concisely the information and analyses conducted in the evaluation process.

Section 7: Description

The evaluation begins with the compilation of a narrative description of the aid to navigation. This description, included in Section 7 of the registration form, should commence with a discussion of the aid to navigation's location, ownership, and status. For example:

The Point Bonita Lighthouse is located on the rocky promontory of Point Bonita, the point projecting out from the northern headlands of the Golden Gate and the entrance into San Francisco Bay. The lighthouse sits at one end of the point; located close by on the steep rocky slopes are a fog signal, bridge, and a tramway leading to the landing and a tunnel that connects the light to a road that in turn leads to the headlands, the location of the keeper's quarters and associated outbuildings and structures. Owned by the U.S. Coast Guard and leased to the National Park Service, Point Bonita Light is undergoing restoration but is open to the public for guided tours.

The description should then identify the type of aid and discuss the specifics of the individual aid. An individual station may have nearly any combination of types of aid to navigation. The aid may be a station composed solely of a light, a light station with sound signal, a sound signal station, or a sound signal station with a light later added. These distinctions are important since stations established solely as sound stations were rare and consequently may possess greater significance. Since the most common type of aid to navigation considered for nomination to the National Register is the lighthouse, which usually is part of or solely forms a light station, most nominations should focus on the specific type of light. The discussion of the evolution of a particular station's purpose and role also helps to establish significance.

The sites of aids to navigation are generally referred to as light stations. These range in complexity from buoy moorings and pile lights to multiple structure and building complexes that supported the operation, provided access to, and housed and supported the keepers of lighthouses. Often several functions are combined in a single structure. Stations may include at least some of the following resources:

  • lighthouse
  • sound signals
  • keepers' quarters (sometimes housed in the same structure as the light)
  • oil house (sometimes housed in the same structure as the light)
  • storage facilities
  • garages, roads, and stables (associated with ground transportation)
  • cisterns (for drinking water and for the boilers of steam-driven fog signals)
  • bridges, tunnels, paths, catwalks (associated with pedestrian access)
  • piers, cranes, davits, landings, boathouses, marine railways (associated with water transportation)
  • cemeteries
  • fences, landscaping
  • tramways and handcars for transportation of residential fuel (coal or cordwood), lamp oil, and supplies
  • wells and privies
  • barns, pigsties, and hen coops
  • sheds (for storage of cordwood, coal, and equipment)
  • vegetable gardens

Exterior Description

The descriptive narrative should focus first on the principal feature of the light station. Lighthouse types and construction methods varied depending on the period, geography, weather, sea conditions, and the availability of materials. The basic characteristic most lighthouses share is a tower of some sort. The characteristics of the tower should be elaborated, including:

  • the shape (e.g., square, conical, octagonal)
  • construction materials
  • construction method
  • the height of the tower
  • dimensions at the base and near the lantern
  • the architectural style or design.

The daymark characteristics of lighthouses differentiated towers. These were often painted patterns or distinctive architectural features. The description of the lighthouse structure should include the foundation type and the reasons for using that foundation in that location. This is particularly necessary when engineering is an area of significance. Architectural features should also be described.

A lighthouse description should begin like this:

"The Cape Disaster Light is a solitary round brick tower that rises 111 feet; at the base the tower is 36 feet in diameter, gradually tapering to 23 feet where the brick tower culminates in the iron lantern. The brick, laid in a common American bond, is unfinished on the interior but is plastered on the exterior. The light is painted with alternating bands of black and white which serve as the distinguishing characteristics of the tower as a daymark. The light has a double set of wood doors at the base with a small stone stoop; above the door, set approximately at the 30-, 60-, and 90-foot levels of the light are three small windows with double hung wood sashes. The lighthouse tower rests on a broad brick pad laid over wooden pilings; this foundation spreads the weight of the tower and supports the lighthouse on the soft, shifting sands of the Cape. "

Interior Description

The nomination should next describe the interior of the lighthouse, particularly if the tower is integral to the keeper's quarters, oil room, or other spaces. Towers might range in complexity from a conical tower with an interior spiral staircase to a multiple component structure. A description of a more complex station might read:

"The Davis Harbor Lighthouse contains three rooms. The central room, entered through the front door, is an open 30 x 20-foot area with a wood floor and a central spiral staircase that ascends to the tower and lantern. A single window and the back door are set into the back wall with doors centered in the side walls. This room served as the parlor of the keeper's quarters. The door on the left (upon entering) leads into the west room, a small 15 x 20-foot area with a wood floor. This was the oil room; originally lined with wood shelves, it has two double-hung wood sash windows, one each on the front and rear walls. When the light was electrified in 1919, the room was converted into a storage area and later into an office. The east room, another 15 x 20-foot area with a wood floor, was divided into two smaller rooms, the kitchen and bedroom. "

Optics and Illuminants

The nomination then should discuss the optic(s) and illuminants used to provide a light signal. Detailed descriptions of every particular lens and lamp employed in the light are not required, but basic information should be mentioned. For example:

"The light was originally lit in 1839 by an Argand lamp with parabolic reflector. In 1857 the light received a 2nd order Fresnel lens illuminated by a five-wick oil lamp which was replaced by an electric incandescent bulb in 1908. In 1947 the significance of the harbor having declined, the light was downgraded to a 4th order Fresnel lens that was removed in 1962. There is currently no optic in the light. "


Descriptions of the optic should cite the elevation of the focal plane above mean high water (not to be confused with the actual height of the tower) and any changes that have occurred. The characteristics of the light, including the use of color and flashing signals, should also be described. These characteristics can be determined for the light by consulting a succession of U.S. Coast Guard Light Lists. (See )

Sound Signals

Another important feature of a light or sound station is the sound signal. Nine basic types of sound signals have been employed in the history of aids to navigation: bells, cannon, whistles, trumpets, diaphones, diaphragm horns, submarine bells, gongs, and electronic tones. A variety of devices have been employed to operate the bells, whistles, horns, and gongs, including clockwork mechanisms, steam, compressed air, and wave motion. The description of a sound signal should note the basic type of signal and then describe the structure and equipment. If a sound signal is no longer present at the site, a detailed description of the equipment is not necessary. A basic notation of type will be sufficient, particularly if the evolution of sound signals at a given station is narrated. For example,

"The emplacement of a 24-pdr. flank howitzer at Point Anderson in 1855 introduced the first fog signal at the light. The gun was fired every 20 minutes in thick fog. In 1861, the gun was replaced by a wooden building housing a bell struck every 90 seconds by a Stevens Automatic Bell Striker. The fog bell was replaced in 1886 by the present building, a single-story brick structure, which originally housed a steam-driven whistle that was replaced with a diaphone in 1916. The diaphone was replaced with a compressed air-driven diaphragm horn which was deactivated in 1978 and replaced by a small electronic tone signal which is presently in use at the site. "

The particulars of extant machinery, including the manufacturer, if known, should be cited (e.g., a Stevens Automatic Bell Striker, or a 2,000-lb. cast bronze bell cast with the raised legend U.S.L.H.E. 1898).


In addition to the daymark feature of particularly marked lighthouses, other daymarks included beacons, pointers, channel markers, painted rocks and other distinctive landmarks that lined channels on rivers, bays, and sounds. Over time many daymarks were lit, first by eight-day oil lanterns, and later by a succession of illuminants. In describing daymarks, either as lights or simple beacons, note whether they are on single piles, dolphins, or skeleton structures. The distinctive markings or shape of the daymark should also be described. This information may be ascertained by consulting the Light List.

Daymark ranges and range or leading lights were paired structures designed to indicate a course to steer or a danger to avoid. The two structures are vertical and separated from one another. They are lined up visually to indicate the bearing of the channel or hazard. These may be small unlit daymarks separated by tens of feet, or large lighthouse towers separated by over a mile. In describing range lights, the distance from each other and the line of bearing should be noted along with the landmark to which they are pointing (e.g., the lights, 3/4 of a mile apart on a 320 degree bearing, pointed out the channel that led into Danielsville Harbor).

Site Layout and Other Features

The interrelationship of the buildings, structures, fences, paths, roadways, plantings, trees, and open space should be described and assessed. The nomination should focus on the concept of a light station as a historic district unless the aid is an isolated automatic aid, such as range lights which were often isolated automated aids to navigation, or river lights, which were usually suspended from poles or mounted on pilings.

The layout of the site should be described. All property features, including the roads, open spaces, alterations to the topography such as road cuts or shaped hillsides to accommodate a light station, plantings, and fences formed the station. Major elements should be described individually and in relationship to each other. Examples of such elements include: large areas covered with cement to form catchment basins for rain water for drinking, washing, and creating steam for the fog signal; cemeteries where keepers and their families were buried, sometimes next to shipwreck victims; or structures designed to combat erosion. Architectural descriptions of any other structures, features, or buildings should then follow. Only extant buildings and structures need to be described in any detail. But those no longer present should be mentioned and their relationship to the surviving features explained: "a 12 x 15-foot single story oil house formerly stood on the road above the light; it was demolished in 1923."


In the Description Section, the integrity of the aid needs to be thoroughly documented, discussing original type, materials, workmanship, and any changes that have occurred through time. Alterations need to be discussed and assessed in relation to the historic context. If a lighthouse was changed, the reasons, such as improved optical or lighting technology, should be noted. Such changes, as stressed earlier, do not necessarily adversely affect the lighthouse's integrity.

Section 8: Statement of Significance

The significance of an aid to navigation is based on its representation of a type, its association with significant themes in American history, and its comparison with similar aids.

The evaluation of an aid to navigation must include thorough historical research into its construction and modifications, including changes to sites, equipment, additions, and operation. Rather than offering just a chronological discussion of a light station's career, the historical narrative included in the Statement of Significance Section of the registration form should be organized into specific context statements. The statements should specify an aid to navigation's place in social, political, economic, architectural, or technological history. This might include a discussion of the following subjects:

  • the development of humanitarian concern for mariners
  • the protection of commerce and transportation
  • the assumption of and increasing responsibility of the federal government in operating aids to navigation
  • American maritime trade, engineering, and commerce
  • the various designs of American lighthouses, lenses, lamps, and sound signals.

Specific historic contexts might involve a lighthouse's place in the development of Colonial lights in North America; the construction, organization, and operation of lights under the Fifth Auditor of the Treasury or the Lighthouse Board; or the changes wrought by the introduction of the Fresnel lens. The historical discussion should enumerate the reasons for establishing the aid, such as numerous shipwrecks or political pressure, as well as factors influencing the selection of a site and construction method, such as logistical or funding problems, and adverse natural conditions.

The significance statement should be concise and well-developed. The information in the nomination will vary according to the aid to navigation's significance to the local community, State, or the Nation. The development of lights on Chesapeake Bay, for example, may be of less significance to a particular lighthouse than its place in the national development of screw pile lighthouses. In discussing significance, link the aid to international, national, regional, and local historic contexts as appropriate. Convey the specific association of a lighthouse to specific historic events. If Criterion B is applicable, an aid to navigation's association with the significant individual(s) should be discussed. Assess the aid's relation to similar properties with similar associations. Derive statements of significance from primary sources and scholarly secondary historical or professional engineering assessments. Thorough historical research is recommended in preparing National Register registration forms so that the best available information is analyzed and presented.

In the Statement of Significance, assess and justify the period during which the property achieved historic significance. The period of significance relates to the date that the current aid to navigation was built or to the dates of significant associations. The period of significance may include the date that the station site was established if significant historic resources with integrity from that period survive. The close of the period of significance might be the disestablishment, automation, or transfer of a site to new owners. For example:

"Lighthouse X, important as a good example of a screw pile light, was built in 1886 on the site of former Lighthouse A, built in 1770. An appropriate period of significance for Lighthouse X would be its date of construction or 1886, not 1770. The period of significance could include the earlier period only if archeological information obtained on the site of Lighthouse A would significantly supplement or revise current historical or archeological knowledge or understanding. "

Section 9: Major Bibliographical References

In Section 9, the bibliography should list sources consulted in the evaluation process as well as those specifically cited. The citations may be organized alphabetically, in categories (such as manuscripts, published works, plans, and collections of historic photographs and other graphics) or in any standard bibliographic style.

Section 10: Geographical Data

The boundary of the aid to navigation, indicated in Section 10 of the registration form, should encompass all nominated historic features described and evaluated in sections 7 and 8. Property boundaries, as long as they do not include large portions of undeveloped land or too many intrusive features (such as a modern housing development built up around a light), may conform to the original surveyed station boundaries. Offshore lights on reefs or shoals should have a boundary encompassed solely by the maximum dimensions of the structure. For example, "Jones Reef Light, 30 x 40 feet on screw piles, as it rests on Jones Reef."

Accompanying Documentation

To assist in the National Register assessment of integrity and significance, individual photographs should illustrate the aid to navigation, its equipment, characteristic and significant features, as well as depiction of changes. Both historic and modern views are useful. Only black and white photographs, ranging in size from 3 1/2" x 5" to 8" x 10" will be accepted. In addition to the required USGS map, it is useful to include a site map preferably with scale, accurately depicting the various resources and any alterations to the geography, such as hillside cuts, tunnels, roads, and plantings or groups of trees. Architectural drawings of aids to navigation, both historic plans and present-day renderings, may be included when available but are not required. If a station has changed significantly over time, a site plan might include earlier plans that depict former and present configurations.

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