Border control in the context of "Federal Police (Germany)"

Borders are generally defined as geographical boundaries, imposed either by features such as oceans and terrain, or by political entities such as governments, sovereign states, federated states, and other subnational entities. Political borders can be established through warfare, colonization, or mutual agreements between the political entities that reside in those areas.

Some borders—such as most states' internal administrative borders, or inter-state borders within the Schengen Area—are open and completely unguarded. Most external political borders are partially or fully controlled, and may be crossed legally only at designated border checkpoints; adjacent border zones may also be controlled. For the purposes of border control, airports and seaports are also classed as borders. Most countries have some form of border control to regulate or limit the movement of people, animals, and goods into and out of the country. Under international law, each country is generally permitted to legislate the conditions that have to be met in order to cross its borders, and to prevent people from crossing its borders in violation of those laws.

The Schengen Area (English: /ˈʃɛŋən/ SHENG-ən, Luxembourgish: [ˈʃæŋən] ) is a system of open borders that encompass 29 European countries that have officially abolished border controls at their common borders. As an element within the wider area of freedom, security and justice (AFSJ) policy of the European Union (EU), it mostly functions as a single jurisdiction under a common visa policy for international travel purposes. The area is named after the 1985 Schengen Agreement and the 1990 Schengen Convention, both signed in Schengen, Luxembourg.

Of the 27 EU member states, only two are not members of the Schengen Area. Cyprus is committed by treaty to join the system and aims to do so by 2026, although its participation has been complicated by the occupation of Northern Cyprus by Turkey since 1974. Ireland maintains an opt-out and operates its own visa policy.

An open border is a border that enables free movement of people and often of goods between jurisdictions with no restrictions on movement and is lacking a border control. A border may be an open border due to intentional legislation allowing free movement of people across the border (de jure), or a border may be an open border due to a lack of legal controls, a lack of adequate enforcement or adequate supervision of the border (de facto). An example of the former is the Schengen Agreement between most members of the European Economic Area (EFTA and the EU). An example of the latter has been the border between Bangladesh and India, which is becoming controlled. The term "open borders" applies only to the flow of people, not the flow of goods and services, and only to borders between political jurisdictions, not to mere boundaries of privately owned property.

Open borders are the norm for borders between subdivisions within the boundaries of sovereign states, though some countries do maintain internal border controls (for example between the People's Republic of China mainland and the special administrative regions of Hong Kong and Macau, between the United States and the unincorporated territories of Guam, the Northern Mariana Islands and American Samoa, and the Minor Outlying Islands, or between North Korea's provinces and cities). Open borders are also usual between member states of federations, though (very rarely) movement between member states may be controlled in exceptional circumstances. Federations, confederations and similar multi-national unions typically maintain external border controls through a collective border control system, though they sometimes have open borders with other non-member states through special international agreements – such as between Schengen Agreement countries as mentioned above.

A border checkpoint is a location on an international border where travelers or goods are inspected and allowed (or denied) passage through. Authorization often is required to enter a country through its borders. Access-controlled borders often have a limited number of checkpoints where they can be crossed without legal sanctions. Arrangements or treaties may be formed to allow or mandate less restrained crossings (e.g. the Schengen Agreement). Land border checkpoints (land ports of entry) can be contrasted with the customs and immigration facilities at seaports, international airports, and other ports of entry.

An entrepôt (English: /ˈɒntrəpoʊ/ ON-trə-poh; French: [ɑ̃tʁəpo] ) is a transshipment port, city, or trading post where merchandise may be imported, stored, or traded, usually to be exported again. Entrepôt also means 'warehouse' in modern French, and is derived from the Latin roots inter 'between' + positum 'position', literally 'that which is placed between'. Typically located on a crossroads, river, canal, or maritime trade route these trade hubs played a critical role in trade during the age of sail. Modern logistics, supply chain networks, and border controls have largely made entrepôts obsolete, or reduced them in number, but the term is still used to refer to duty-free ports or those with a high volume of re-export trade.

Railways, Container Ships, Air-Freight, and Telecommunications have created a world in which commodities and manufactured goods are shifted from one part of the globe to another in regular, controlled, and reliable streams; see Just-in-Time Manufacturing. Eliminating the factors which once made the entrepot phenomenon central to trade networks. But, as pointed out by the Dutch economist T.P. van der Kooy and has been more recently restated by P.W. Klein, before the Industrial Revolution the flow of goods from one part of the world to another, even one region of a country to another, was so irregular and unpredictable that there was no possibility of achieving any sort of steady distribution, any balancing of supply and demand, or any sort of price stability except by stockpiling great reserves of commodities in central storehouses; ie entrepots.

The Great Wall of China (traditional Chinese: 萬里長城; simplified Chinese: 万里长城; pinyin: Wànlǐ Chángchéng, literally "ten thousand li long wall") is a series of fortifications in China. They were built across the historical northern borders of ancient Chinese states and Imperial China as protection against various nomadic groups from the Eurasian Steppe. The first walls date to the 7th century BC; these were joined together in the Qin dynasty. Successive dynasties expanded the wall system; the best-known sections were built by the Ming dynasty (1368–1644).

To aid in defense, the Great Wall utilized watchtowers, troop barracks, garrison stations, signaling capabilities through the means of smoke or fire, and its status as a transportation corridor. Other purposes of the Great Wall have included border controls (allowing control of immigration and emigration, and the imposition of duties on goods transported along the Silk Road), and the regulation of trade.

The area of freedom, security and justice (AFSJ) of the European Union (EU) is a policy domain concerning home affairs and migration, justice as well as fundamental rights, developed to address the challenges posed to internal security by collateral effects of the free movement of people and goods in the absence of border controls or customs inspection throughout the Schengen Area, as well as to safeguard adherence to the common European values through ensuring that the fundamental rights of people are respected across the EU.

In general, a port of entry (POE) is a place where one may lawfully enter a country. It typically has border security staff and facilities to check passports and visas and to inspect luggage to assure that contraband is not imported. International airports are usually ports of entry, as are road and rail crossings on a land border. Seaports can be used as ports of entry only if a dedicated customs presence is posted there. The choice of whether to become a port of entry is up to the civil authority controlling the port.

A border barrier, border fence or border wall is a separation barrier that runs along or near an international border. Such barriers are typically constructed for border control purposes such as curbing illegal immigration, human trafficking, and smuggling. Some such barriers are constructed for defence or security reasons. In cases of a disputed or unclear border, erecting a barrier can serve as a de facto unilateral consolidation of a territorial claim that can supersede formal delimitation. A border barrier does not usually indicate the location of the actual border, and is usually constructed unilaterally by a country, without the agreement or cooperation of the other country.

Examples of border walls include the ancient Great Wall of China, a series of walls separating China from nomadic empires to the north. The construction of border barriers increased in the early 2000s; half of all the border barriers built since World War II, which ended in 1945, were built after 2000.

An international airport is an airport with customs and border control facilities, enabling passengers to travel between countries around the world. International airports are usually larger than domestic airports, and feature longer runways and have facilities to accommodate heavier aircraft such as the Boeing 747 and the Airbus A380 commonly used for international and intercontinental travel. International airports often host domestic flights, which helps feed both passengers and cargo into international ones (and vice versa).

Buildings, operations, and management have become increasingly sophisticated since the mid-20th century, when international airports began to provide infrastructure for international civilian flights. Detailed technical standards have been developed to ensure safety and common coding systems implemented to provide global consistency. The physical structures that serve millions of individual passengers and flights are among the most complex and interconnected in the world. By the second decade of the 21st century, over 1,200 international airports existed with around 3.8 billion international passengers as of January 2023 along with 50 million metric tonnes of cargo passing through them annually.

The Johor–Singapore Causeway is a 1.056-kilometre (0.66 mi) causeway across the Straits of Johor. The Causeway links Johor Bahru in Malaysia to Woodlands in Singapore. It is one of the busiest border crossings in the world, with 350,000 road and rail travellers daily. The under construction Johor Bahru–Singapore Rapid Transit System is expected to relieve The Causeway's traveller numbers by 35% upon opening, currently scheduled for December 2026. The Causeway also serves as a water pipeline between the two countries.

The Causeway officially opened in 1923. Its construction interrupted the water flow through the Straits of Johor, especially after the post World War II permanent closure of the lock channel. Retreating Allied forces blew up The Causeway in two places in World War II. That forced the advancing Imperial Japanese Army to instead cross the Straits elsewhere.

A travel visa (from Latin charta visa 'paper that has been seen'; also known as visa stamp) is a conditional authorization granted by a polity to a foreigner that allows them to enter, remain within, or leave its territory. Visas typically include limits on the duration of the foreigner's stay, areas within the country they may enter, the dates they may enter, the number of permitted visits, or if the individual can work in the country in question. Visas are associated with the request for permission to enter a territory and thus are, in most countries, distinct from actual formal permission for an alien to enter and remain in the country. In each instance, a visa is subject to border control at the time of actual entry and can be revoked at any time. Visa evidence most commonly takes the form of a sticker endorsed in the applicant's passport or other travel document but may also exist electronically. Some countries no longer issue physical visa evidence, instead recording details only in border security databases.

Some countries require that their citizens, and sometimes foreign travelers, obtain an exit visa in order to be allowed to leave the country.

The Boundaries of Hong Kong, officially the Boundary of the Administrative Division of the Hong Kong Special Administrative Region of the People's Republic of China (Chinese: 中華人民共和國香港特別行政區行政區域界綫), is a regulated administrative border with border control in force under the One country, two systems constitutional principle, which separates the Hong Kong Special Administrative Region from mainland China, by land border fence of 30 km (19 mi) and maritime boundary of 733 km (455 mi), enforcing a separate immigration and customs-controlled jurisdiction from mainland China.

The boundaries of Hong Kong are patrolled and controlled by the Hong Kong Police Force and its Marine Region and the Immigration Department at land and sea. The land boundary also includes a buffer zone, known as Frontier Closed Area.

The United States Department of Homeland Security (DHS) is the U.S. federal executive department responsible for public security, roughly comparable to the interior, home, or public security ministries in other countries. Its missions involve anti-terrorism, civil defense, immigration and customs, border control, cybersecurity, transportation security, maritime security and sea rescue, and the mitigation of weapons of mass destruction.

It began operations on March 1, 2003, after being formed as a result of the Homeland Security Act of 2002, enacted in response to the September 11 attacks. With more than 240,000 employees, DHS is the third-largest Cabinet department, after the departments of Defense and Veterans Affairs. Homeland security policy is coordinated at the White House by the Homeland Security Council. Other agencies with significant homeland security responsibilities include the departments of Health and Human Services, Justice, and Energy.