Table of Contents

About US Domain

The US Domain is an official top-level domain in the DNS of the Internet. It is administered by the US Domain Registry at the Information Sciences Institute of the University of Southern California (ISI).

US is the ISO-3166 2-letter country code for the United States and thus the US Domain is established as a top-level domain and registered in the same way as other country domains. Figure 1 shows the relationship between the US domain and other top level domains.

Figure 1: A View of the Top Level Domain

Who can Register

Anyone can register under the US Domain as long as the naming structure is followed.

The US Domain currently registers businesses, individuals, federal government agencies, state government agencies, K12 schools, community colleges, technical/vocational schools, private schools, libraries, museums, and city and county government agencies.

Any computer in the United States may be registered in the US Domain hierarchy. Generally, computers outside the United States are expected to register in other domains, however, there may be exceptions when a computer is used as part of a project or in a community with other computers in the US Domain.

Naming Structure

The US Domain hierarchy is based on political geography. The basic namespace under US is the state name space, then the "locality" name space (like a city or county), then organization or computer names, and so on (for example: The state codes are those assigned by the US Postal Service (for example: "CA" is the state code for California). Figure 2 shows a view of second level domains under US.

Figure 2: A View of Second Level Domains

In addition to strictly geographical names, some special affinity names are used, such as FED, STATE, K12, LIB, CC, TEC, GEN, DST, COG, MUS, ISA and NSN (these are explained under the Special Domain Names). Under the name space are CI and CO subdomains, and under K12 is PVT.

Generally, it is expected that a name will correspond to a physical computer and that a computer will have exactly one name.

Locality Names

Within the state name space there are "locality" names, which may be cities, or counties (parishes or townships), or local names.

For small entities like individuals or small businesses there is usually no problem with selecting locality based names. For example:


For large entities like large corporations with multiple facilities in several cities or states this often seems like an unreasonable constraint (especially when compared with the alternative of registering directly in the COM domain). However, a company does have a head office in a particular locality and so could register with that name. For example:

The locality based domain names are the fundamental concept for naming in the US Domain. All other subdomains or branches are exceptions. See Figure 3 for locality view. Registered names under "locality" would include:

<agencyname>.CI.<locality>.<state>.US (city government agency)
<agencyname>.CO.<locality>.<state>.US (county government agency)
<agencyname>.<locality>.<state>.US (businesses, private schools)

In the cases where the locality name is a county, there is a branch under the locality name, called "CO", that is used by the county government. Businesses are registered directly under the locality name.

Under the city locality name space there is a "CI" branch for city government agencies (some localities may use other names such as TOWN, VILLAGE, BOROUGH, or PARISH). As usual, businesses and private schools may register directly under the city name.

In the case where there is both a county and a city with the same locality name there is no problem, since the names will be unique with the "CO" or "CI". For example, when the county has a fire department and the city has its own fire department, they could have names like:

Cities are named (designated) by their full name (spelled out with hyphens replacing spaces (e.g., Santa-Monica or Fort-Collins). In a few cases in the past, a well-known city abbreviation known throughout a locality was allowed; eventually these abbreviated names will be replaced with the fully spelled out versions. It is very desirable that all users in the same city use the same designator for the city. That is, any particular locality should have just one domain name.

An agency of the city government takes on the responsibility for the delegation of the domain (for example: CI.Ventura.CA.US) and can register all the other agencies under the CI code for the locality like Fire-Dept.CI.Ventura.CA.US. In the same way the county government can take the responsibility for the delegation (for example: CO.Ventura.CA.US) and register all the agencies under it like Fire-Dept.CO.Ventura.CA.US.

Acceptable locality names are those listed in the US Postal Service Zip Code Directory or a well known atlas.

There is no requirement, as far as the overall US domain administration is concerned, that the user of a "locality" US domain name actually be in or have any connection with that locality. For example, the user of Smith.Boston.MA.US could actually reside in New Hampshire.

Figure 3: Locality View

K12 Schools Under The US Domain:

K12 schools are connecting to the Internet and registering in the Internet Domain Name System. A decision has been made by the Internet Assigned Numbers Authority (after consultation with the InterNIC Internet Registry and the Federal Network Council (FNC)) to direct these school registrations to the US Domain using the naming structure described here (see Figure 4). Only four year colleges and universities may now be added to the EDU domain. Two year community colleges and technical schools are also registered in the US Domain. K12 schools are registered in the US Domain with names of the general form:


Generally school names are unique within a district, and this provides two points at which to delegate a branch of the database to distinct administrators -- the K12 administrator for each state, and the district administrator for each school district within a state.

Examples of K12 Public School Names and Districts

riverdale-hs.K12.TN.US (Riverdale High School)
northstar.K12.AK.US (North Star School District)
prs.K12.NJ.US (Princeton Regional School District )

Figure 4: K12 School View

Schools Connected Through Network Providers

Schools should be named in the K12 branch rather than having names under the name of a network consortium or service provider. Deriving a school name from a service provider is like having the name of your telephone company as part of your organization name.

Summary of Entities That Go Under K12

Schools public and private
School districts
School boards
Special Education Service Units
State Departments of Education
City and County Departments of Education
Consortiums connecting school districts and schools
State Agencies connecting K12 schools
School Networks providing connectivity to school districts

School Related Entities In Other US Domain Branches

FED - Military Schools Overseas
For example: K12.DODDS.FED.US

STATE - State Departments of Education
For example: DOE.STATE.IN.US

LOCALITY - City or County Departments of Education
For example: ED.CO.TULARE.CA.US
- Private K12 schools

Private Schools

To accommodate both public and private schools, in each state's K12 branch, an artificial district called private or "PVT" is available. This gives a private school the option of registering like a business under "locality" or in the PVT.K12.<state-code>.US branch.

Community College And Technical Vocational Schools

To distinguish colleges and Technical/Vocational schools, the keywords CC and TEC have been created. Figure 5 shows a view of these schools. Community colleges and Junior colleges are generally two year colleges sometimes offering an Associate of Arts degree. The courses offered at Community and Junior colleges are usually the equivalent of the first two years of a 4 year college.

Technical and Vocational schools usually offer courses and training leading to specific specialized skills in a particular subject or technology.The naming structure for community colleges and technical/vocational schools in the form:


Figure 5: Community College View

State Agencies

Many states are setting up networks to interconnect the offices of state government agencies. The hosts in such networks should be registered under the STATE.<state-code>.US branch. See RFC 2146 US Government Internet Domain Names for how government agencies should register. Figure 6 shows a state view.

Figure 6: State View

Special Domain Names

Name Space Within States

  1. LOCALITY - Cities, Counties, Parishes, and Townships
    The is the basic naming structure of the US Domain (i.e., businesses,
    individuals, private schools, city and county agencies).
    For example: <host-name>.<locality>.<state-code>.US.

    -- CI - City Government Agencies
    This branch is a subdomain under the <locality> name
    (like Santa-Monica) for the city government. For example:

    -- CO - County Government Agencies
    This branch is a subdomain under the <locality> name
    (like San-Bernardino) for the county government. For example:

  2. K12 - Public Schools, Districts
    This branch is used for Kindergarten through 12th grade
    schools and districts. For example:

    -- PVT - Private Schools
    A special name "PVT" may be used in the place
    of a school district name for private schools. For example:

  3. CC - Community Colleges
    This branch was established for all statewide community
    colleges. For example:

  4. TEC - Technical and Vocational Schools
    This branch was established for technical
    and vocational schools and colleges. For example:

  5. LIB -Libraries (State, Regional, City, County)
    This branch is used for public and private libraries,
    as well as library networks, consortiums, and systems.
    For example: <library-name>.LIB.<state-code>.US.

  6. STATE -State Government Agencies
    This branch may be used for state agencies.
    For example:<org-name>.STATE.<state-code>.US.

  7. GEN -General Independent Entities
    This branch is used for state-wide non-profit organizations,
    such as clubs, etc. For example:

  8. COG - Councils of Government
    This branch is used for federations of cities or counties
    or their sub-agencies to work on particular issues on a
    regional basis forming councils of government. For example:

  9. MUS - Museums
    This branch is used for museums. For example:

  10. DST - Districts (DST replaces District)
    This branch is for governmental agencies in districts that
    may or may not have common boundaries with cities
    or counties, or general administrative districts, such as
    water supply, and resource management. For example:

Names Parallel to States

  1. FED - Federal Government
    This branch is used for agencies of the federal government.
    For example: <org-name>.FED.US.

  2. NSN - Native Sovereign Nations
    This branch is used for North American Indian Nations, comprising
    Indian tribes, villages, rancherias, colonies,
    and other Indian communities that can span state, regional, and
    national boundaries. The tribes listed in the Bureau of Indian Affairs
    "Federally Recognized Indian Tribes" can register under NSN.
    For example:<indian-nation>.NSN.US.

  3. ISA - Interstate Authority
    This branch is used for joint governmental authorities that
    are multi-state. For example, the Port Authority of New York
    and New Jersey.


Registrations are by delegation, where a branch of the US Domain is delegated to an organization running name servers to support that branch.

All K12 schools, community colleges/technical schools, and state and local government agencies are encouraged to register under the US Domain. For registration in other top level domains such as COM, NET, and ORG see the ICANN web site at for a list of all current registrars, for EDU contact Network Solutions, Inc. at, and for GOV contact

To request a copy of the US Domain Template, send a message to the or use the template available online.

If you are registering a name in a zone that has been delegated, please mail your registration directly to the contact for the subdomain in which you want to register. The contact list for the subdomains delegated is available at Delegated Subdomains and their Contacts.


Most branches of the US Domain are delegated. Typical delegations are localities (cities or counties), companies within cities, K12 schools, community colleges, libraries, state and federal government agencies. Examples of delegations are K12.TX.US for Kindergarten through 12th grade public schools in Texas, BERKELEY.CA.US for the locality Berkeley in California, or LIB.MN.US for the libraries in Minnesota.

Acceptable locality names are those listed in the US Postal Service Zip Code Directory or a well-known atlas.

Administrative and Technical Responsibilities

There must be a knowledgeable and competent technical contact familiar with the Internet Domain Name System. We do not provide technical support. We only register the domain names.

Organizations requesting delegations must provide at least two independent (robust and reliable) DNS name servers in physically separate locations on the Internet. The servers should be active and responsive to DNS queries BEFORE the application is submitted. Incomplete information about the servers and IP addresses or inactive servers will result in delay of the registration. The subdomain administrator must accept all applicants on an equal basis and provide timely processing of requests.

You must set your host computers to accept zone transfers from the US Domain Registry.

The subdomain manager must notify the US Domain Registrar immediately about any changes in the name servers that should be reflected in the US Domain zone files, or changes in the administrative and technical contact information. Administrators must follow the guidelines in the current US Domain RFC and assist applicants in selecting a domain name.

The contact phone number given to the US Domain Registrar should be answered during normal business hours. All messages received after business hours should be answered the next working day. This is required to resolve problems either by US Domain or by the customer directly. If we receive many complaints or experience any problems ourselves in getting touch with the delegated manager the delegation may be revoked.

Policy on the Number of Domains

Some domain managers have taken on the responsibility for managing a large number of locality domains. To promote diversity, no single domain manager (person or company) should be responsible for more than 50 localities in one state, or 500 localities in total.

Some domain managers have more 50 localities in one state. Those delegations were done prior to this rule. The above rule cannot be applied to those managers.

Policy on Delegation of Locality

The policy given below cannot be applied to the domains that were delegated before 1-Jul-97.

For delegations (or redelegations) made after 1-Jul-97, it is assumed by the US Domain Administrator that every applicant for the delegation (or redelegation) of a locality name has the written agreement of the legitimate government for that locality for the applicant to manage the domain name of that locality.

Evidence of such an agreement does not need to be presented at the time of delegation (except that the administrative contact on the application template must be the government representative). However, if the delegation is later challenged or contested, the manager of the locality domain must produce the agreement. Failure to do so will most likely result in the transfer of the management of the locality domain to another manager that does have such an agreement.

If there is a dispute as to who is the legitimate government for a locality and who may act for it, the league of cities or association of municipalities in that state (as recognized by the National League of Cities) may be asked to assist in resolving such disputes.

In some places there are overlapping jurisdictions with the same name (for example, the city of Los Angeles and the county of Los Angeles). In such cases, the higher level government should have priority.

Policy on Misrepresentation of Information

A new policy has been added to avoid several cases of misleading, erroneous, and outright false information provided on registration applications.

One situation that occurs is that one individual represents himself as several distinct companies in order to bypass some limitations on the number of delegations allowed (e.g., the 50/500 rule).

Another situation is with the requirement to provide a government employee as the administrative contact for a locality delegation. Some applications have been received with a government employee's contact information but that person has no idea that such an application has been submitted. Some applications provide contact information for an individual that knows what is going on but is not an employee of the locality government. Still other applications have been received where the administrative contact information is fictional.

The US Domain Registrar may choose to verify any or all of the information on registration applications (including the administrative contact) and if it is determined that the an application contains false or substantially misleading information that application may be denied, or if already acted on the delegation may be revoked, and in either case all other delegations made to the party submitting the false or misleading application may also be revoked.

Delegation of the Special Domains

The special domains (K12, CC, TEC, LIB, MUS, STATE, DST, COG and GEN) under each state are established for special purposes (defined in RFC 1480 ).

In addition to the constraint to use them only for the defined purpose, each of these special domains is also delegated only to a manager within the state, and the operation of the delegated registry should be non-profit.

The LIB and MUS domains should be managed by a govermental or educational institution.

Further, it is most appropriate for the K12, CC, and TEC, domains to be managed by an educational organization (for example, a university or a department of education).

The STATE domain is most appropriately managed by an agency of the state government. DST and COG should be managed by a goverment agency.

The GEN domain may be delegated to a state organization that will provide the registration service for free (the purpose of GEN is to register statewide non-profit organizations). If we determine that these domains are being charged for, then all the domains delegated to that organization will be taken back. The same organization cannot have the delegation of GEN for two states.


The InterNIC has developed the RWHOIS program which supports distributed databases of WHOIS information. This allows for the reduction of queries and referral of information to be closer to the maintainer of the information.

The US Domain Registry has installed a client/server RWHOIS protocol to support the US Domain WHOIS information. We request that the administrator of a subdomain of the US Domain should also operate a RWHOIS server for those subdomains under them. For more information contact The data from the information you supplied on your application will be used for your WHOIS entry. Currently, we provide third-level delegations in the US Domain WHOIS database. For example: K12.IL.US would have an entry in the US WHOIS database:

venera 37% whois -h %RWhois V-1.0: (by InterNIC Registration Services V-1.0B9.2) Illinois K12 Schools (K12-IL-US-DOM) K12 schools in Illinois CICNet 2901 Hubbard Dr. Ann Arbor, MI 48105 Domain Name: K12.IL.US Administrative Contact: Krol, Ed (EK10-US) (217) 333-7886 (FAX) 217-244-7089 Technical Contact: Veach, R. Ross (RV80-US) RRV@UIUC.EDU (217) 244-4274 Registration Information: Record Last Updated on Jan-13-98. Domain servers in listed order: NS.UIUC.GEN.IL.US NS2.OAR.NET
The RWHOIS information is not available for fourth-level domains (example, We expect the manager of the third-level domains (example, to provide RWHOIS information for those domains. Please use tools such as "dig" or "nslookup" for server information about these domains.

The RWHOIS for domains under .US is maintained by the US Domain Registry and not by the InterNIC.

The WHOIS information for IP addresses and most nameservers are maintained by the InterNIC. To modify those please email


Currently, there is no cost charged by the US Domain administrator for delegating a locality or other branch of the US Domain at that level.

Most managers of delegated branches do not charge for registering a host in the US domain in their localities, though some do. There is no requirement that domain names be free, only that any charges be fair and applied equally to all customers.

In the past, managers provided the nameservers and registration services for localities (and other branches of the US domain) for free. Some people came forward to provide this public service, and it is very much appreciated.

Many locality names in the US domain are delegated to small companies. These companies need to charge a small fee to set up and maintain the database and run the nameservers to support this service.

In the current environment of the Internet, it is reasonable for locality managers to charge a small fee for domain name service under the US domain delegations.

Each locality domain manager is responsible for setting his own fees or billing practices and deciding what is "small". For example, some of these companies are charging $10 per year.

In a some instances, a domain name previously allocated by the US Domain administrator may be passed on to a new locality manager during delegation. The new administrator of the locality has to notify such name holders one year in advance before charging for those domains.


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the US Domain Registry. Thank you. Last modified 25-Oct-99.