.us is the Internet country code top-level domain (ccTLD) for the United States. It was established in February 1985. Registrants of us domains must be U.S. citizens, residents, or organizations – or foreign entities with a presence in the United States or a territory of the United States. Most registrants in the U.S. have registered for .com, .net, .org and other gTLDs, instead of us, which has primarily been used by state and local governments, even though private entities may also register us domains. The domain is managed by Registry Services, LLC, an acquired subsidiary domain name registry of GoDaddy, on behalf of the United States Department of Commerce.
The us domain is less commonly used by American businesses and enterprises than the internationally more common .com.
History On February 15, 1985, us was created as the Internet's first ccTLD. Its original administrator was Jon Postel of the Information Sciences Institute (ISI) at the University of Southern California (USC). He administered us under a subcontract that the ISI and USC had from SRI International (which held the us and the gTLD contract with the United States Department of Defense) and later Network Solutions (which held the us and the gTLD contract with the National Science Foundation).
Postel and his colleague Ann Westine Cooper codified the us ccTLD's policies in December 1992 as RFC 1386 and revised them the following June in RFC 1480. Registrants could only register third-level domains or higher in a geographic and organizational hierarchy. From June 1993 to June 1997, Postel delegated the vast majority of the geographic subdomains under us to various public and private entities. us registrants could register with the delegated manager for the specific zone they wished to register in, but not directly with the us administrator. In July 1997, Postel instituted a "50/500 rule" that limited each delegated manager to 500 localities maximum, 50 in a given state.
In June 1998, Postel raised the possibility of covering IANA operating costs by charging locality name registrars, who would pass the costs along to individual registrants. In September 1998, the United States Postal Service proposed funding the operations in order to assume control of us, as part of a plan to diversify away from postage revenue. On October 1, 1998, the NSF transferred oversight of the us domain to the National Telecommunications and Information Administration (NTIA) of the United States Department of Commerce.Requesting comments on draft statement of work regarding us Postel died that month, leaving his domain administration responsibilities with ISI. In December 2000, these responsibilities were transferred to Network Solutions, which had recently been acquired by Verisign.Amendment 21 to the NSI Cooperative AgreementTHE GLOBALISATION OF REGULATION AND ITS IMPACT ON THE DOMAIN NAME SYSTEM : DOMAIN NAMES AND A NEW REGULATORY ECONOMY by ELIZABETH A WILLIAMS
On October 26, 2001, Neustar was awarded the contract to administer us. On April 24, 2002, second-level domains under us became available for registration. One of the first us domain hacks, icio.us, was registered on May 3, 2002, for the creation of the subdomain del.icio.us.Whois query for the domain names "DELICIO.US" and "ICIO.US". Whois database last updated March 29, 2015. Accessed March 29, 2015. A moratorium was placed on additional delegations of locality-based namespaces, and Neustar became the default delegate for undelegated localities.Manheim, Karl M. and Solum, Lawrence B., "An Economic Analysis of Domain Name Policy" (2004). University of San Diego Law and Economics Research Paper Series. 1. http://digital.sandiego.edu/lwps_econ/art1 Neustar's contract was renewed by the National Telecommunications and Information Administration (NTIA) in 2007, 2014, and most recently in 2019 for a term of 10 years.
On March 31, 2019, the us registry made it clear that under its Acceptable Use Policy it would not allow the sale of opioids through the us top level domain.
In Q2 2020, GoDaddy acquired Neustar's registry business.
Locality namespace The us ccTLD is historically organized under a complex locality namespace hierarchy. Until second-level registrations were introduced in 2002, us permitted only fourth-level domain registrations of the form ...us, with some exceptions for government entities. Registrants of locality-based domains must meet the same criteria as in the rest of the us ccTLD. Though the locality namespace is most commonly used for government entities, it is also open to registrations by private businesses and individuals. Since 2002, second-level domain registrations have eclipsed those in the locality namespace, and many local governments have transitioned to .org and other TLDs. In the 2010s, the first top-level domains for U.S. cities became available as paid alternatives to third-level locality domains, including .nyc as an alternative to .new-york.ny.us.
Many locality-based zones of us are delegated to various public and private entities known as delegated managers. Domains in these zones are registered through the delegated manager, rather than through GoDaddy. As the delegated managers are expected to receive requests directly from registrants, few if any domain name registrars serve this space, possibly contributing to its lower visibility and utilization. RFC 1480 describes the rationale for the locality namespace's deep hierarchy and local delegation:
This hierarchical system has proven unappealing to companies that operate nationally or globally.
As of October 31, 2013, 12,979 domains were registered under the locality namespace, of which 3,653 were managed by about 1,300 delegated managers while 9,326 were managed by Neustar as the de facto manager. According to a 2013 survey of 539 delegated managers, 282 were state or local government agencies, while 98 were private individuals and 85 were commercial Internet service providers. Nearly 90% of the respondents offer domain registrations for free.
The .au and .ca ccTLDs have also established third- and fourth-level locality namespaces, though the .ca locality namespace is no longer open to registrations. The .cn ccTLD maintains a third-level locality namespace in general use.
States and territories A two-letter second-level domain is formally reserved for each U.S. state, federal territory, and the District of Columbia. Each domain corresponds to a USPS abbreviation. For example, .ny.us is reserved for websites affiliated with New York, while .va.us is for those affiliated with Virginia. Second-level domains are also reserved for five U.S. territories: .as.us for American Samoa, .gu.us for Guam, .mp.us for the Northern Mariana Islands, .pr.us for Puerto Rico, and .vi.us for the U.S. Virgin Islands. However, these domains go unused because each territory has its own ccTLD per ISO 3166-1 alpha-2: respectively, .as, .gu, .mp, .pr, and .vi.
A state's main government portal is usually found at the third-level domain state..us, which is reserved for this purpose. However, some state administrations prefer .gov domains: for example, California's government portal is located at . Other than for state governments, no third-level domain registrations are permitted under state or territory second-level domains.
A few additional names are reserved at the second level for government agencies that are not subordinate to a state government:
fed.us for agencies of the U.S. federal government (historical; superseded by .gov) Example: (formerly the United States Forest Service) isa.us for interstate authorities created by interstate compacts Example: (Interstate Mining Compact Commission) nsn.us for Native Sovereign Nations (which may also use -nsn.gov) Example: (Mohegan Tribe) dni.us for distributed national institutes Example: (formerly the Conference of Chief Justices, part of the National Center for State Courts) Example: (formerly the Theta Delta Chi fraternity)
Locality domains A large number of third-level domains are reserved for localities within states. Each fourth-level domain registration under this namespace follows the format ...us, where is a state's two-letter postal abbreviation and is a hyphenated name that corresponds to a ZIP code or appears in a well-known atlas.
Two values of are formally reserved across the entire locality namespace for city and county governments:
ci...us for city governments Example: (East Palo Alto, California), (Mansfield, Ohio) co...us for county governments Example: (Adams County, Idaho)
Delegated managers often reserve additional names for different kinds of local governments:
borough...us for borough governments Example: (Shippensburg, Pennsylvania) city...us for city governments Example: (Waltham, Massachusetts) county...us for county governments parish...us for parish governments (unused) town...us for town governments Example: (Northlake, Texas), (Windermere, Florida) twp...us or township...us for township governments Examples: (Jerusalem Township, Lucas County, Ohio), (Wilson Township, Winona County, Minnesota), twp.greene.franklin.pa.us (Greene Township, Franklin County, Pennsylvania) vil...us or village...us for village governments Examples: (Bellwood, Illinois), (Fairport, New York)
In some cases, a local government that serves as the delegated manager for its own locality may locate its website directly under the , omitting the . For example, the website of the City of Brunswick, Ohio, is located at rather than www.ci.brunswick.oh.us, and the website of Delhi Township, Ohio, is located at instead of www.twp.delhi.oh.us. Unusually, Lima, Ohio, is located at .
Many large cities use .gov extensions, for example Chicago (); Rochester, New York and (). Several cities, villages, and towns use the .gov format, often with the state abbreviated, for example, Atlanta, Georgia (), Northport, New York (), and Huntington, New York (). Although most New York City websites have moved to , us redirects exist for individual city agencies, such as the Independent Budget Office at and the Board of Elections at .
Private organizations and individuals may register fourth-level domains parallel to these government domains, for example:
(a community network in Boulder, Colorado) (the neighborhood council for Hyde Park, Cincinnati) (Portland Linux/Unix Group) (Michael Silverton, a resident of Palo Alto, California) or (a family in San Jose, California) (the neighborhood association for Hope, Providence, Rhode Island) (a Mastodon instance in Seattle) (a Mastodon instance in Tulsa, Oklahoma) (a Linux user group in Chicago) (The WELL, a virtual community in San Francisco)
The us TLD registrar serves as the default delegated manager for all undelegated third-level locality domains, as well as any locality domains relinquished by delegated managers. Under Neustar and GoDaddy, the registrar has discontinued delegation of third-level locality domains, as well as registration of domain names under any locality or affinity domain for which it serves as the delegated manager.
Alternative locality names Some delegated managers alternatively register domains under common abbreviations of locality names, which are not necessarily interchangeable. Many of these abbreviations came from Western Union's "City Mnemonics" list. Examples include: