Frequently Asked Questions

Mapping, Remote Sensing, and Geospatial Data

The USGS provides the mapping and digital geospatial foundation for the Nation.

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Public Land Survey System
The Public Land Survey System (PLSS) is a way of subdividing and describing land in the United States. PLSS surveys, which are available for portions of land in 30 southern and western states, are made by the Bureau of Land Management (BLM). The PLSS typically divides land into 6-mile-square townships. Townships are subdivided into 36 one-mile-...
longitude convergence
All coordinates in the Geographic Names Information System database are in the North American Datum of 1983 (NAD 83). They were converted from the North American Datum of 1927 (NAD 27) in September 2005.
Image: Natural Entrance at Carlsbad Caverns
Geographic Names Informations System (GNIS) entries for caves are in the database but cannot be retrieved on the public website. In response to the 1988 National Cave Management Resources Act, Department of the Interior Regulation 43 (CFR Subtitle A, Part 37) forbids the release of information regarding the location of all caves on Federal lands....
Everglades National Park sign
Coordinates that seem to be incorrect in the Geographic Names Information System might just be projected on a different datum from the datum used on your map or your positioning system (GPS).  Most USGS maps published approximately 1940-1995 are projected on the North American Datum of 1927 (NAD27). Later maps are projected on the North American...
muddy Willamette River
The Geographic Names Information System (GNIS) contains named communities--both incorporated and unincorporated--but these communities do not necessarily correspond to ZIP Code areas. ZIP Codes are unofficial entities developed and maintained by the U.S. Postal Service solely for delivering mail. ZIP Code areas are named by the Post Office for the...
Participant in LCMAP workshop looks at computer screen
Suggested corrections and additions to the Geographic Names Information System (GNIS) data are accepted from any source for review. Upon validation, they will be committed to the database. For manmade and administrative features, submit the official name of the feature with its precise location in geographic coordinates (latitude/longitude), the...
National Elevation Dataset
The elevation figures in the Geographic Names Information System (GNIS) are not official and do not represent precisely measured or surveyed values. Only the geographic name and locative attributes are official. Elevations are derived from data in The National Map. The data are interpolated from seamless raster elevation models for the given...
Alaska Surveying
Yes, The Geographic Names Information System (GNIS) actively seeks names of features that no longer exist. The term "historical" as used in the GNIS specifically means that the feature no longer exists on the landscape. An abandoned ghost town, for example, still exists so it is not historical. Historical features have no reference to age, size,...
Photo of Advanced Research Computing (ARC) "Yeti" supercomputing cluster
Please report possible errors to the Geographic Names Information System Manager at BGNEXEC@usgs.gov. The Names data experts will investigate and validate the data, enter appropriate corrections where needed, and advise you of the results. Learn more: U.S. Board on Geographic Names: Principles, Policies, and Procedures
I will never forget the first time I saw Denali. Even from Anchorage, over 100 miles away, I could see a massive mound of white
Proposals to change the name of a natural feature can be submitted to the U.S. Board on Geographic Names. There must, however, be a compelling reason to change it. The Board is responsible by law for standardizing geographic names throughout the Federal Government and discourages name changes unless necessary. Further, changing a name merely to...
Person looking extremely small as they stand under a giant sandstone arch
Proposals to name an unnamed natural feature can be submitted to the Board on Geographic Names (BGN). The BGN is responsible by law for standardizing geographic names throughout the Federal Government, and promulgates policies governing issues such as commemorative naming, derogatory names, and names in wilderness areas.  Please note that no...
Wheeler Peak with Glacier
There are no official definitions for generic terms as applied to geographic features. Any existing definitions derive from the needs and applications of organizations using those geographic features. The Geographic Names Information System (GNIS) database utilizes 63 broad categories of feature types defined solely to facilitate retrieval of...