A customs territory is a geographic territory with uniform customs regulations and there are no internal customs or similar taxes within the territory. Customs territories may fall into several types:
- A sovereign state, including a federation
- A trade bloc that has a customs union
- An autonomous or dependent territory 
There are also some unregulated lands (usually uninhabited) not part of any customs territory.
As of 2010, most customs unions rarely operate as a single entity and are represented in relations with other customs territories either jointly by their member state governments and the union institutions or by only the member states. Thus, in practice, they rarely appear as a single customs territory and instead they operate as a multiple separate customs territories that have the same or similar customs tariffs. The European Union (EU) is the only trade bloc in which the union institutions have exclusive competence over the common external tariff and thus sign and ratify agreements with foreign states without direct participation of the EU member states. The EU is also the only trade bloc member of the World Trade Organization, but the EU member states also continue their own separate memberships, as not all of the WTO issues fall within the scope of exclusive EU competences.
The governing organs (government or other responsible administrative entity for the states and territories, secretariat or similar international organization body for the trade blocs) of the customs territories negotiate and sign trade agreements. In some cases the negotiations are conducted by a trade bloc secretariat, but the actual agreement is signed by the member states of the trade bloc. It is also possible for a group of customs territories, that do not form a customs union (regardless if they cooperate as a different type of trade bloc), to negotiate trade agreements together and to sign the resulting agreement individually (for example, the European Free Trade Association).
A customs territory usually has inspection stations at its borders. There can also be border checks between two parts of the same customs territory. For example, there are border checks between the Schengen Area portions of the EU customs territory and those portions in the Common Travel Area formed by the United Kingdom, Crown Dependencies, and Ireland. Another example is the border checks between Israel and the Palestinian Territories, which are in a customs union. The European Union example is particularly complicated, since it also has different boundaries for EU VAT area, the EU excise duty area, the area where EU law applies, and the area considered by the EU statistics agency.
List of customs territories
Sovereign states (including freely associated states), which typically have independent customs policies, are enumerated on the list of sovereign states. These include both freely associated states and partially recognized states.
- Andean Community of Nations (CAN)
- Caribbean Community (CARICOM)
- Antigua and Barbuda
- Saint Kitts and Nevis
- Saint Lucia
- Saint Vincent and the Grenadines
- Trinidad and Tobago
- Other CARICOM member states, The Bahamas and Haiti are not a part of the customs union arrangement although Haiti is in the process of acceding.
- East African Community (EAC)
- Eurasian Customs Union
- European Union Customs Union (internal border checks) - includes the territory of European Union member countries, excepting many areas outside of continental Europe, and some exclaves and border areas that belong to the customs territory of Switzerland. (See Special member state territories and the European Union for a detailed list.) Various treaties extend the EU customs area to include the non-EU states of:
- Israel — Palestinian Authority customs union (internal border checks)
- Southern Common Market (MERCOSUR)
- Southern African Customs Union (SACU)
- Switzerland — Liechtenstein — Büsingen am Hochrhein customs union (no external border checks)
The customs territory of the United States includes the fifty states, the District of Columbia, and Puerto Rico. The following dependent United States territories are outside the customs territory and most administer customs separately:
- American Samoa - Government of American Samoa
- Guam - Government of Guam
- Northern Mariana Islands - Government of the Commonwealth of the Northern Mariana Islands
- United States Minor Outlying Islands
- Wake Island - Department of the Air Force General Counsel
- Midway Islands - Department of the Navy
- Johnston Atoll - none
- (Other islands are uninhabited, although Palmyra Atoll, administered by the Fish and Wildlife Service, is permanently staffed and has several private land parcels. It has no customs administration or duties.)
- US Virgin Islands - Federal rules as modified by the Virgin Islands legislature, but implemented by U.S. Customs and Border Protection
- Special Administrative Region of the People's Republic of China
- Republic of China (Taiwan) (officially titled as Separate Customs Territory of Taiwan, Penghu, Kinmen, and Matsu or Chinese Taipei in the WTO)
The following dependent territories have independent customs policies from the main part of the sovereign country of which they are a part:
- Anguilla (British Overseas Territory)
- Aruba (Netherlands territory)
- Bermuda (British Overseas Territory)
- Bouvet Island (Norway territory)
- British Indian Ocean Territory (British Overseas Territory)
- Caribbean Netherlands (special municipalities of the Netherlands)
- Cayman Islands (British Overseas Territory)
- Ceuta (Spanish territory)
- Christmas Island (Australian territory)
- Cocos (Keeling) Islands (Australian territory)
- Curaçao (Netherlands territory)
- Falkland Islands (British Overseas Territory)
- Faroe Islands (Danish territory)
- French Polynesia (French territory)
- French Southern and Antarctic Lands (French territory)
- Gibraltar (British Overseas Territory)
- Greenland (Danish territory)
- Heard and McDonald Islands (Australian territory)
- Melilla (Spanish territory)
- Montserrat (British Overseas Territory)
- New Caledonia (French territory)
- Norfolk Island (Australian territory)
- Pitcairn Islands (British Overseas Territory)
- Saint Helena, Ascension and Tristan da Cunha (British Overseas Territory)
- Saint Pierre and Miquelon (French territory)
- Sint Maarten (Netherlands territory)
- South Georgia and the South Sandwich Islands (British Overseas Territory)
- Tokelau (New Zealand territory)
- Turks and Caicos Islands (British Overseas Territory)
- British Virgin Islands (British Overseas Territory)
- Wallis and Futuna (French territory)
- List of free ports
- Customs area
- Economic integration
- Special Member State territories and the European Union - multiple separate customs territories
- List of World Customs Organization member states
- For example: Interim Agreement on trade and trade-related matters between the European Community, of the one part, and the Republic of Montenegro, of the other part.
- see the list of customs unions for references
- "New Separatist Recruits for Russia's Customs Union". Eurasianet.
- Some of the special EU member state territories are covered by EU law (Art.52 TEU and Art.355 TFEU), but nevertheless remain outside the EU customs territory. "Annex 1: Overview of European Union countries" (PDF). Retrieved 21 Apr 2014.
- 19 CFR 101.1
- 19 CFR 7.2
- Separate Customs Territory of Taiwan, Penghu, Kinmen and Matsu (Chinese Taipei), World Trade Organization, retrieved 2014-09-10,
Chinese Taipei has been a member of WTO since 1 January 2002.