Internet top-level domain

Country code TLDs

Two-letter top-level domains are assigned to countries and dependent teritories by ICANN. Main criteria for ICANN is ISO country codes list, but ICANN and ISO lists differ a little.

As of 05.02.2020 ISO list contains 249 officially assigned codes.

As of 05.02.2020 ICANN's IANA Root Zone Database contains 255 two-latin-letters country-code domains, including 249 ISO-assigned codes + AC (Ascension - while it is part of Saint Helena, Ascension and Tristan da Cunha territory in SH ISO code), AN (former Netherlands Antilles, divided into BQ, CW and SX), EU (European Union), SU (Soviet Union), TP (former Portuguese Timor, renamed to Timor-Leste since independence) and UK (United Kingdom, along with GB for Great Britain - domain GB is Reserved and works for only one 2nd-level domain name hmg.gb - stands for 'Her Majesty Government' - with several subdomains but no websites on them).

248 domains are online. Domains BL (Saint Barthélemy), BQ (Bonaire, Sint Eustatius and Saba), EH (Western Sahara), MF (Saint Martin) and UM (U.S. Minor Outlying Islands) are marked as Not assigned. AN and TP marked as Retired (.tp was deleted from nameservers 26.01.2015; .an deleted in July 2015 or later).

ISO codes

ISO codes are based on United Nations Statistics Division list. UNSD Country or Area Codes for Statistical Use list includes as separate entry Sark island (since 2011).

12 ISO codes are exceptionally reserved at requests of countries and organisations:

AC Ascension Island             Exceptionally reserved at the request of Universal Postal Union (UPU)
CP Clipperton Island            Exceptionally reserved at the request of International Telecommunication Union (ITU)
DG Diego Garcia                 Exceptionally reserved at the request of International Telecommunication Union (ITU)
EA Ceuta and Melilla            Exceptionally reserved at the request of World Customs Organization (WCO)
EU European Union               Exceptionally reserved at the request of ISO 4217/MA (Currencies) for ISO 6166 (Securities)
EZ (European OTC derivatives)   Exceptionally reserved at the request of ISO 6166/RA (Securities)
FX France, Metropolitan         Exceptionally reserved at the request of France
IC Canary Islands               Exceptionally reserved at the request of World Customs Organization (WCO)
SU USSR                         Exceptionally reserved at the request of the Foundation for Internet Development (FID)
TA Tristan da Cunha             Exceptionally reserved at the request of Universal Postal Union (UPU)
UK United Kingdom               Exceptionally reserved at the request of United Kingdom
UN United Nations               Exceptionally reserved by the ISO 3166 Maintenance Agency

Reserved codes AC, EU, SU and UK are delegated as Internet TLDs. AC registrars position it as Academic domain; EU stands for European Union; SU - for Post-Soviet states; UK is being used instead of ISO-assigned GB code.

7 ISO codes are transitionally reserved for 50 years after renaming of countries or dissolution of federations and dependent territories:

BU Burma                 Reserved from 1989-12 to 2039-12. New country name: Myanmar                   MM
NT Neutral Zone          Reserved from 1993-07 to 2043-07. Divided between Iraq and Saudi Arabia     IQ+SA
ZR Zaire                 Reserved from 1997-07 to 2047-07. New country name: Congo (Kinshasa)          CD
TP East Timor            Reserved from 2002-05 to 2052-05. New country name: Timor-Leste               TL
YU Yugoslavia            Reserved from 2003-07 to 2053-07. New country name: Serbia and Montenegro     CS
CS Serbia and Montenegro Reserved from 2006-09 to 2056-09. Divided to Serbia and Montenegro          RS+ME
AN Netherlands Antilles  Reserved from 2010-12 to 2060-12. Divided (see below)                      BQ+CW+SX

.AN was deleted by ISO on 2010-12-15/2011-12-13 - and is still transitionally reserved to Netherlands Antilles (divided into: Bonaire, Sint Eustatius and Saba - BQ, Curaçao - CW and Sint Maarten - SX).