The FIPS 10-4 standard, Countries, Dependencies, Areas of Special Sovereignty, and Their Principal Administrative Divisions, was a list of two-letter country codes that were used by the U.S. Government for geographical data processing in many publications, such as the CIA World Factbook. The standard was also known as DAFIF 0413 ed 7 Amdt. No. 3 (November 2003) and as DIA 65-18 (Defense Intelligence Agency, 1994, "Geopolitical Data Elements and Related Features").
The FIPS 10-4 codes are similar to (but sometimes incompatible with) the ISO 3166-1 alpha-2 country codes. The standard also includes codes for the top-level subdivision of the countries, similar to but usually incompatible with the ISO 3166-2 standard.