Frequently Asked Questions

a lake of lily pads and trees in the middle
Reelfoot Lake, Tennessee

Photo by Hornal

AnchorWhat is a National Natural Landmark (NNL)?

It is a natural area that has been designated by the Secretary of the Interior in recognition that the site contains significant examples of the nation's biological and/or geological features.

AnchorHow is national significance for NNLs defined?

The site must be one of the "best" examples of a type of biological community or geological feature in its biophysiographic province. "Best" is gauged primarily on illustrative value and condition of the resource

When and how was the National Natural Landmarks Program established?

It was established in 1962 by administrative action relying on authority provided by the Historic Sites Act of 1935. Three other laws subsequently referenced the program. The first NNLs were designated in 1964.

Who manages the NNL Program?

The NNL Program is managed by the National Park Service, Department of the Interior. For questions please contact the appropriate NNL Coordinator as determined by state.

What are the goals of the NNL Program?

The goals are to encourage the preservation of sites illustrating the geological and ecological character of the United States, to enhance the scientific and educational value of sites thus preserved, to strengthen public appreciation of natural history, and to foster a greater concern for the conservation of the nation's natural heritage.

What types of natural features are considered for NNL designation?

Natural features include terrestrial and aquatic ecosystems;geological features, exposures, and landforms that record active geological processes or portions of earth history;and fossil evidence of biological evolution. Features fall within major natural history "themes" that can be further subdivided into various sub-themes. For example, subthemes for the overall theme "Lakes, Ponds, and Wetlands" include large deep lakes, large shallow lakes, lakes of complex shape, crater lakes, kettle lake and potholes, oxbow lakes, dune lakes, Sphagnum-bog lakes, lakes fed by thermal streams, tundra lakes and ponds, sinkhole lakes, unusually productive lakes, lakes of high productivity and high clarity, swamps, marshes, bogs, fens, wet meadows, and springs.

Why are NNLs important?

Besides fostering the basic program goals of natural heritage protection and advancing science and education, some NNLs are the best remaining examples of a type of feature in the country and sometimes in the world.

Are lands excluded from NNL consideration based on ownership?

No. Lands under almost all forms of ownership or administration have been designated--federal, state, county, municipal, tribal, and private.For example, federal lands with NNLs include those administered by the National Park Service, U.S. Forest Service, Bureau of Land Management, Bureau of Reclamation, Fish and Wildlife Service, Air Force, Marine Corps, Army Corps of Engineers, Navy, and others.Some occur on lands held by Native Americans or tribes. NNLs occur on state lands with various existing management designations--forest, park, game refuge, recreation area, and preserve. Private lands with NNLs include those owned by universities, museums, scientific societies, conservation organizations, land trusts, commercial interests, and private individuals.Approximately 52% of NNLs are administered by public agencies, more than 30% are entirely privately-owned, and the remaining 18% are owned or administered by a mixture of public agencies and private owners.

How many NNLs are there?

As of December 2023, there are 604 NNLs that have been designated within the United States and American Territories.

How do I find out about NNLs in my State?

A map showing all NNLs by state can be found by visiting the NNL Directory.

How large are NNLs?

They vary in size from less than four acres to over 900,000 acres.

Are NNLs usually single features?

Some are, like Dinosaur Trackway, Connecticut. However, other NNLs encompass very large, diverse landscapes with many different ecological and geological features like Nipomo Dunes-Point Sal Coastal Area, California.

Do NNLs include famous places I might know about?

Some NNLs are well known. The volcanic crater Diamond Head on the Island of Oahu, Hawaii, the Okefenokee Swamp in Georgia, and the Rancho La Brea tar pits in Los Angeles, California are designated as NNLs. However, many NNLs have unfamiliar names due to a number of factors: they are usually not primary tourist destinations, may not be open to the public, are often small, and may be difficult to access.

Do NNL boundaries coincide with other protected area boundaries?

Not always. The focus of the NNL boundary is to circumscribe the nationally significant resources, and thus may or may not coincide with an administrative boundary. NNLs are often smaller tracts within larger national forests, national wildlife refuges, state parks, and state recreation areas. However, NNLs may coincide with the boundaries of other designations, such as Forest Service Research Natural Areas or Bureau of Land Management Areas of Critical Environmental Concern.

Are NNLs open to the public?

Some are and others are not. Participation in the NNL Program does not carry any requirements for public access. Since many NNLs are located on federal and state property, permission to visit is often unnecessary. Some private property may be open to public visitation or just require a go-ahead from the site manager. On the other hand, some NNL private landowners do not desire any visitors whatsoever and might even prosecute trespassers. The reasons for this viewpoint vary: potential property damage or liability, fragile or dangerous resources, and desire for no publicity or solitude.

How are NNLs selected?

The process to identify candidate sites, evaluate, and designate them as NNLs includes the following steps:
  1. An inventory of a natural region is completed to identify the most promising sites.
  2. Landowners within the area identified for evaluation are notified and their permission obtained prior to evaluation of the site.
  3. A detailed site evaluation is conducted by qualified scientists.
  4. The evaluation report is peer-reviewed by an additional three qualified scientists to ensure its soundness.
  5. The report is reviewed by the National Park Service, and if the site appears to meet the criteria for national significance, the site owners are notified and comment is sought from the public on the proposal to designate the site as an NNL.
  6. The National Park System Advisory Board reviews the evaluation report and public comments and makes a recommendation on the proposed designation.
  7. All materials and recommendations are sent to the Secretary of the Interior, who may then designate the site as an NNL.
  8. Landowners and the public are notified of the NNL designation by letter and publication of a Federal Register Notice.

Do regulations govern the NNL Program?

Yes. The first program regulations were developed in 1980. The current regulations were revised in the 1990s and published in the Federal Register on May 12, 1999 as 36 CFR Part 62. The NNL Program regulations dictate administration of the program by the National Park Service, but not NNL land use or management. The NNL Federal Regulation can be accessed here.

Does NNL designation change property ownership?


What type of agreement is involved?

There is no formal written agreement between NNL landowners and the National Park Service. The landowner's permission for NNL evaluation is considered an agreement to participate in the program.

Is NNL designation permanent?

Yes, although the Secretary of the Interior can remove the NNL designation if the resources for which the site was designated are lost or destroyed. NNL designation may also be removed if it can be shown that there were errors in professional judgment or in the designation process.

Does NNL designation invoke land use restrictions?

The federal action of designation imposes no new land use restrictions that were not in effect before the designation. It is conceivable that State or local governments on their own volition could initiate regulations or zoning that might apply to an NNL. Some states require planners to ascertain the location of NNLs and consider potential impacts from proposed projects.

Does NNL designation affect land values?

We have no studies that allow a well-informed answer to this question. An effect on land values would depend on individual property and perception in the local area as to whether NNL status denotes a positive effect or not.

Can NNL landowners do whatever they wish with their property?

Basically, yes. However, participation in the NNL Program involves a voluntary commitment on the part of the landowner(s) to retain the integrity of their NNL property as it was when designated. If major habitat or landscape destruction is planned, participation in the NNL Program by a landowner would be ingenuous and meaningless.

How are NNLs protected?

NNL protection is achieved primarily through the conservation efforts of the landowners. The National Park Service may also act as an advocate for conservation of the NNL resources if this is requested by the landowners.

What are the benefits to landowners who participate?

There are few, tangible direct benefits. Some examples follow:
  1. Proposed projects that are federally funded or require federal permits, which have the potential to affect NNL resources (e.g., highway construction, river channelization), must comply with the requirements of the National Environmental Policy Act (NEPA). Impacts to NNL resources would be disclosed and avoided or mitigated. This is a form of protection, though there is no guarantee that such a federal project will not damage the NNL.
  2. NNL program staff may assist landowners with conservation or interpretation of the site's resources through project planning, obtaining grants, securing technical assistance, and writing letters in support of protecting the NNL resources if they are threatened.
  3. The foremost incentive afforded to NNL landowners is being in a position to voluntarily preserve an important part of Americas natural heritage, which indirectly benefits all citizens. A plaque and certificate are provided by the National Park Service, which honors that commitment.

Does each owner get a plaque?

No, the cost of the plaques prohibits this. Plaques are usually displayed at a location that is mutually agreeable to the participating landowners. However, certificates may be provided to numerous NNL owners.

Can the National Park Service provide NNL landowners with funds to manage NNL resources?

Not typically. However, National Park Service staff look for grant opportunities and can provide assistance to NNL landowners with preparation of proposals and letters of support.

Does the National Park Service visit NNLs?

Yes. NNL program regulations require the National Park Service to monitor the condition of NNLs to ensure that they retain the illustrative value and condition that qualified them for NNL designation. A site visit report is compiled detailing condition of resources and identifying any known or anticipated damage or threats, the source of threats/damage, and any actions being taken to reduce threats and damage to NNL resources.

Are NNLs expected to be protected and managed according to standards that apply to national parks?

No. Policies germane to national parks do not transfer to NNLs just because the National Park Service manages the NNL Program. However, key guiding principles for national parks (e.g., maintain the resource "unimpaired" or in a "natural condition") would be compatible with one NNL Program goal (i.e., not diminish the site's "natural integrity").

If a NNL is damaged, will NNL designation be removed?

It is possible that NNL status could be removed if the values that originally qualified the site for designation were lost. If this were to occur, the site would be removed from the National Registry of Natural Landmarks and the National Park Service would request that the NNL plaque be returned.

Are NNLs designated as a first step in becoming units of the National Park System?

No. The criteria for designating NNLs and National Park System units are different. For an area to become a unit of the National Park System, it must pass National Park Service criteria of suitability and feasibility. Furthermore, Congress would have to authorize the unit's establishment. Of the 604 NNLs, only 26 are located within 21 different units of the National Park System.

Does the NNL Program operate like the National Historic Landmarks Program or the National Register of Historic Places?

No, there are many important differences. The National Historic Landmarks (NHL) Program is augmented by additional legislation that allows the Advisory Council on Historic Preservation to review and comment on federally owned, assisted, or licensed undertakings that may affect properties included or eligible for inclusion in the National Register of Historic Places, which includes all NHLs. The National Register of Historic Places lists sites of national significance and those of state and local significance as well.

How do NNLs relate to other natural area preservation efforts?

It is only one of many programs. The following criteria distinguish NNLs from other U.S. natural area inventory and protection activities:
  1. The NNL Program is national in scope,
  2. All land ownership categories are included,
  3. The NNL Program places a focus on the best examples of resources, and
  4. Geologic and biological resources receive equal emphasis.

Where do I go for further information?

If you have further questions please contact the appropriate NNL Coordinator as determined by state.

Last updated: December 13, 2023


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