This is a list of heritage NATO country codes. Up to and including the seventh edition of STANAG 1059, these were two-letter codes (digrams). The eighth edition, promulgated 19 February 2004, and effective 1 April 2004, replaced all codes with new ones based on the ISO 3166-1 alpha-2 codes. Additional codes cover gaps in the ISO coverage, deal with imaginary countries used for exercise purposes, and designate large geographical groupings and water bodies (ranging from oceans to rivers). It consists of two-letter codes for geographical entities, four-letter codes for subdivisions, and lists the ISO three-letter codes for reference. The digrams match the FIPS 10-4 codes with a few exceptions. The ninth edition's ratification draft was published on 6 July 2005, with a reply deadline of 6 October 2005. It replaces all two- and four-letter codes with ISO or ISO-like three- and six-letter codes. It is intended as a transitional standard: once all NATO nations have updated their information systems, a tenth edition will be published. For diplomatic reasons, the country that is now known as North Macedonia was designated as the Former Yugoslav Republic of Macedonia for a number of years and received a temporary code, FY/FYR, explicitly different from the ISO one, which was 3166 MKD. Since its name change following the 2018 Prespa agreement with Greece, the country is identified with the MK digram and the MKD trigram, but on car license plates, they must be changed to NM or NMK. The Republic of Palau is also often indicated (at least in the United States) as PW.

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