The function of the Registry of Geography (ROG) is to document standardized codes for geopolitical areas. The Editor and Steward of the Registry of Geography is Loren Muehlius, LightSys .

The Geopolitical Entities, Names, and Codes (GENC) Standard has replaced the retired FIPS 10-4.

  • Geopolitical Entities, Names, and Codes (GENC) Standard. GENC specifies a profile of ISO 3166 Codes for the representation of names of countries and their subdivisions. It starts with the entries from ISO 3166 (Parts 1 and 2) and accepts all of its codes and names that meet U.S. government requirements. This enables the U.S. government standard to be better aligned with the international standard than FIPS 10-4 was, while providing U.S. management of the profile to ensure that U.S. recognition and naming constraints are satisfied. Although ISO 3166 supports both two- and three-character codes, there are conflicts between the FIPS 10-4 two-character codes and the ISO 3166-1 two-character codes that prohibit an easy transition. For that reason, the U.S. Government is moving to three-character codes. Changing from two to three characters, especially in legacy systems, requires a significant transition period, and not all historical data can be moved into a new paradigm.

To browse the GENC codes, go to, To search the GENC codes, go to To download the codes go to, Choose the Country Codes button to download 3 letter codes and names. Use the ADM1 Codes button to download the admin 1 codes of all countries.

Previously this registry referenced codes for Countries, Dependencies, Areas of Special Sovereignty, and Their Principal Administrative Divisions, as detailed in the Federal Information Processing Standard (FIPS) 10-4, used by the U.S. Government. The FIPS 10-4 standard was withdrawn as a Federal Information Processing Standard in 2008. The National Geospatial-Intelligence Agency continued to maintain FIPS 10-4 through 31 December 2014, at which point it was officially retired.

  • ISO 3166 Country Codes. ISO 3166 is the International Standard for country codes and codes for their subdivisions. The purpose of ISO 3166 is to define internationally recognized codes of letters and/or numbers that can be used to refer to countries and subdivisions. However, it does not define the names of countries – this information comes from United Nations sources (Terminology Bulletin Country Names and the Country and Region Codes for Statistical Use maintained by the United Nations Statistics Divisions).

The full list of ISO 3166-1 Country codes can be viewed on the ISO Online Browsing Platform (OBP).

The full list of ISO 3166-2 Subdivision codes is available for purchase from the ANSI Webstore.

For a comparison table between GENC, GEC (formerly FIPS 10-4), ISO codes, and two other country coding systems see CountryCodeCrossReference2023-04-12.xls and column definitions in CountryCodeCrossReference.pdf.