Country Code Top-Level Domains (ccTLDs) are a category of Internet top-level domains typically reserved for a country, a sovereign state, or a territory with a country code. All ASCII-encoded ccTLD identifiers are two letters long, and nearly all two-letter top-level domains are ccTLDs.
In 2018, the Internet Assigned Numbers Authority (IANA) began implementing internationalized ccTLDs, which appear in end-user applications with characters from their respective languages. The creation and delegation of ccTLDs are described in RFC 1591, corresponding to the ISO 3166-1 alpha-2 country codes. While Generic Top-Level Domains (gTLDs) must comply with international regulations, ccTLDs must adhere to requirements set by the domain management authorities of their respective countries. As of 2022, there are over 150 million registered ccTLDs, accounting for about 40% of the entire domain name industry.
The application for ccTLDs began in 1985. That year, ccTLDs registered included .us (United States), .uk (United Kingdom), and .il (Israel). In 1986, ccTLDs registered included .au (Australia), .de (Germany), .fi (Finland), .fr (France), .is (Iceland), .jp (Japan), .kr (South Korea), .nl (Netherlands), and .se (Sweden). In 1987, ccTLDs registered included .nz (New Zealand), .ch (Switzerland), and .ca (Canada). In 1988, ccTLDs registered included .ie (Ireland), .it (Italy), .es (Spain), and .pt (Portugal). In 1989, ccTLDs registered included .in (India) and .yu (Yugoslavia). During the 1990s, .cn (China) and .ru (Russian Federation) were first registered.
As of May 20, 2017, there were 255 two-character code ccTLDs composed of pure Latin letters. By June 2020, with the addition of internationalized domain names, this number increased to 316.
Among them, .cn (China), .tk (Tokelau), .de (Germany), .uk (United Kingdom), .nl (Netherlands), and .ru (Russia) have the highest number of domain registrations. The top ten ccTLDs account for more than two-thirds of all registered ccTLD domain names. As of the end of March 2022, about 153 million ccTLDs were registered.
The Internet Corporation for Assigned Names and Numbers (ICANN) is responsible for determining the appropriate manager for each country's top-level domain (ccTLD). The management and control rights are then delegated to that manager, who is responsible for the domain's policies and operations. The current delegation status can be determined through IANA's list of country-code top-level domains. Different ccTLDs may have varying requirements and fees for registering subdomains. There may be requirements for local presence (e.g., citizenship or other ties to the ccTLD), such as for the United States (us), Japan (jp), Canada (ca), France (fr), and Germany (de) domains, or the registration may be open.
The first registered country-code top-level domain (ccTLD) was .us, registered in 1985. Later that year, .uk and .il were also registered. Then, in 1986, .au, .de, .fi, .fr, .is, .jp, .kr, .nl, and .se were also registered. By 1987, .nz, .ch, .my, and .ca were registered as well. Subsequently, in 1988, .ie, .it, .es, and .pt were registered.