The Geographic Names Information System (GNIS) is a database that contains name and locative information about more than two million physical and cultural features located throughout the United States of America and its territories. It is a type of gazetteer. GNIS was developed by the United States Geological Survey in cooperation with the United States Board on Geographic Names (BGN) to promote the standardization of feature names.
The database is part of a system that includes topographic map names and bibliographic references. The names of books and historic maps that confirm the feature or place name are cited. Variant names, alternatives to official federal names for a feature, are also recorded. Each feature receives a permanent, unique feature record identifier, sometimes called the GNIS identifier.  The database never removes an entry, "except in cases of obvious duplication." 
The GNIS accepts proposals for new or changed names for U.S. geographical features. The general public can make proposals at the GNIS web site and can review the justifications and supporters of the proposals.
- The Bureau of the Census defines Census Designated Places as a subset of locations in the National Geographic Names Database.
- U.S. Postal Service Publication 28 gives standards for addressing mail. In this publication, the postal service defines two-letter state abbreviations, street identifiers such as boulevard (BLVD) and street (ST), and secondary identifiers such as suite (STE).
- Canadian Geographical Names Data Base, a similar, but non-public-domain, database for locations within Canada only
- GEOnet Names Server, a similar database for locations outside the United States
- United Nations Conference on the Standardization of Geographical Names