ISO 3166-1 alpha-2

ISO 3166-1 alpha-2 codes are two-letter country codes defined in ISO 3166-1, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), to represent countries, dependent territories, and special areas of geographical interest. They are the most widely used of the country codes published by ISO (the others being alpha-3 and numeric), and are used most prominently for the Internet's country code top-level domains (with a few exceptions). They were first included as part of the ISO 3166 standard in its first edition in 1974.
The ISO 3166-1 alpha-2 codes are used in different environments and are also part of other standards. In some cases they are not perfectly implemented.
The ISO 3166-1 alpha-2 codes are used in the following standards:
Starting in 1985, ISO 3166-1 alpha-2 codes have been used in the Domain Name System as country code top-level domains (ccTLDs). The Internet Assigned Numbers Authority currently assigns the ccTLDs mostly following the alpha-2 codes, but with a few exceptions. For example, the United Kingdom, whose alpha-2 code is GB, uses .uk instead of .gb as its ccTLD, as UK is currently exceptionally reserved in ISO 3166-1 on the request of the United Kingdom.
The WIPO coding standard ST.3 is based on ISO 3166-1 alpha-2 codes, but includes a number of additional codes for international intellectual property organizations, which are currently reserved and not used at the present stage in ISO 3166-1.
The European Commission generally uses ISO 3166-1 alpha-2 codes with two exceptions: EL (not GR) is used to represent Greece, and UK (not GB) is used to represent the United Kingdom. This notwithstanding, the Official Journal of the European Communities specified that GR and GB be used to represent Greece and United Kingdom respectively. For VAT administration purposes, the European Commission uses EL and GB for Greece and the United Kingdom respectively.
The United Nations uses a combination of ISO 3166-1 alpha-2 and alpha-3 codes, along with codes that pre-date the creation of ISO 3166, for international vehicle registration codes, which are codes used to identify the issuing country of a vehicle registration plate; some of these codes are currently indeterminately reserved in ISO 3166-1.
IETF language tags (conforming to the BCP 47 standard track and maintained in an IANA registry) are also partially derived from ISO 3166-1 alpha-2 codes (for the region subtags). The full list of ISO 3166-1 codes assigned to countries and territories are usable as region subtags. Also, the "exceptionally reserved" alpha-2 codes defined in ISO 3166-1 (with the exception of UK) are also usable as region subtags for language tags. However, newer stability policies (agreed with ISO) have been implemented to avoid deleting subtags that have been withdrawn in ISO 3166-1; instead they are kept and aliased to the new preferred subtags, or kept as subtags grouping several countries. Some other region grouping subtags are derived from other standards. Under the newer stability policies, old assigned codes that have been withdrawn from ISO 3166-1 should no longer be reassigned to another country or territory (as has occurred in the past for "CS").
The following is a colour-coded decoding table of all ISO 3166-1 alpha-2 codes.
The following is a complete list of the 249 current officially assigned ISO 3166-1 alpha-2 codes, with the following columns:
User-assigned code elements are codes at the disposal of users who need to add further names of countries, territories, or other geographical entities to their in-house application of ISO 3166-1, and the ISO 3166/MA will never use these codes in the updating process of the standard. The following alpha-2 codes can be user-assigned: AA, QM to QZ, XA to XZ, and ZZ. For example:
Furthermore, the code element OO is designated as an escape code if the number of regular user-assigned code elements is not sufficient.
Reserved code elements are codes which have become obsolete, or are required in order to enable a particular user application of the standard but do not qualify for inclusion in ISO 3166-1. To avoid transitional application problems and to aid users who require specific additional code elements for the functioning of their coding systems, the ISO 3166/MA, when justified, reserves these codes which it undertakes not to use for other than specified purposes during a limited or indeterminate period of time.
The reserved alpha-2 codes are divided into the following three categories: exceptional reservations, transitional reservations, and indeterminate reservations.
Exceptionally reserved code elements are codes reserved at the request of national ISO member bodies, governments and international organizations, which are required in order to support a particular application, as specified by the requesting body and limited to such use; any further use of such code elements is subject to approval by the ISO 3166/MA. The following alpha-2 codes are currently exceptionally reserved:
The following alpha-2 codes were previously exceptionally reserved, but are now officially assigned:
Transitional reserved code elements are codes reserved after their deletion from ISO 3166-1. These codes may be used only during a transitional period of at least five years while new code elements that may have replaced them are taken into use. These codes may be reassigned by the ISO 3166/MA after the expiration of the transitional period. The following alpha-2 codes are currently transitionally reserved:
The following alpha-2 code was previously transitionally reserved, but was later reassigned to another country as its official code:
For each deleted alpha-2 code, an entry for the corresponding former country name is included in ISO 3166-3. Each entry is assigned a four-letter alphabetic code, where the first two letters are the deleted alpha-2 code.
Indeterminately reserved code elements are reserved for use in a particular way, usually due to their presence in other coding systems. For example, several codes are reserved because they are used for international intellectual property organizations in WIPO Standard ST.3. The following alpha-2 codes are currently indeterminately reserved:
The following alpha-2 codes were previously indeterminately reserved, but have been reassigned to another country as its official code:
Besides the codes currently transitionally reserved and two other codes currently exceptionally reserved (FX for France, Metropolitan and SU for USSR), the following alpha-2 codes have also been deleted from ISO 3166-1:
For each deleted alpha-2 code, an entry for the corresponding former country name is included in ISO 3166-3. Each entry is assigned a four-letter alphabetic code, where the first two letters are the deleted alpha-2 code.