A closed city or town is a settlement where travel or residency restrictions are applied so that specific authorization is required to visit or remain overnight. Such places may be sensitive military establishments or secret research installations that require much more space or internal freedom than is available in a conventional military base. There may also be a wider variety of permanent residents, including close family members of workers or trusted traders who are not directly connected with clandestine purposes. Many closed cities existed in the Soviet Union during the Cold War. Following the dissolution of the Soviet Union in 1991, a number of them continue to exist in the post-Soviet states, especially in Russia. In modern Russia, such places are officially known as "closed administrative-territorial formations".

Structure and operations

Closed cities are sometimes represented only on classified maps that are not available to the general public. In some cases, there may be no road signs or directions to closed cities, and they are usually omitted from railroad timetables and bus routes. Sometimes, closed cities are indicated obliquely as a nearby insignificant village, with the name of the stop serving the closed city made equivocal or misleading. For mail delivery, a closed city is usually named as the nearest large city and a special postcode, for example, Arzamas‑16, Chelyabinsk‑65. The actual settlement can be rather distant from its namesakes; for instance, Sarov, designated Arzamas-16, is in the federal republic of Mordovia, whereas Arzamas is in Nizhny Novgorod Oblast (roughly 75 km away). People not living in a closed city were subject to document checks and security checkpoints, and explicit permission was required for them to visit. To relocate to a closed city, one would need security clearance by the organization running it, such as the KGB in Soviet closed cities. Closed cities were sometimes guarded by a security perimeter with barbed wire and towers. The very fact of such a city's existence was often classified, and residents were expected not to divulge their place of residence to outsiders. This lack of freedom was often compensated by better housing conditions and a better choice of goods in retail trade than elsewhere in the country. Also, in the Soviet Union, people working with classified information received a salary bonus.

Soviet-era

Closed cities were established in the Soviet Union from the late 1940s onwards under the euphemistic name of "post boxes", referring to the practice of addressing post to them via mailboxes in other cities. They fell into two distinct categories. The locations of the first category of closed cities were chosen for their geographical characteristics. They were often established in remote places deep in the Urals and Siberia, out of reach of enemy bombers. They were built close to rivers and lakes that were used to provide the large amounts of water needed for heavy industry and nuclear technology. Existing civilian settlements in the vicinity were often used as sources of construction labour. Although the closure of cities originated as a strictly temporary measure that was to be normalized under more favorable conditions, in practice the closed cities took on a life of their own and became a notable institutional feature of the Soviet system. Any movement to and from closed areas was tightly controlled. Foreigners were prohibited from entering them and local citizens were under stringent restrictions. They had to have special permission to travel there or leave, and anyone seeking residency was required to undergo vetting by the NKVD and its successor agencies. Access to some closed cities was physically enforced by surrounding them with barbed wire fences monitored by armed guards.

Mailbox

"Mailbox" was the unofficial name of a secret Soviet facility much like the closed city, but smaller, usually the size of a factory. The name of such a facility was usually secret, as were the activities there. Incoming mail was addressed to "Mailbox #XXXX", thus the name of "mailbox". Most Soviet design bureaus (OKB) for weapons, aircraft, space technology, military electronics, etc., were "mailboxes".

Post-Soviet

Russia

Russia has the largest number of closed cities globally. The policy governing these cities underwent significant changes in the late 1980s and early 1990s. The adoption of a new constitution for the Russian Federation in 1993 prompted substantial reforms to the status of closed cities, which were subsequently renamed "closed administrative-territorial formations" (or ZATO, from the Russian acronym). Municipally, all such entities have the status of urban okrugs, as mandated by federal law. There are 44 publicly acknowledged closed cities in Russia with a total population of approximately 1.5 million people. Seventy-five percent are administered by the Russian Ministry of Defense, with the remainder under the administration of Rosatom. It is believed that about 15 additional closed cities exist, but their names and locations have not been publicly disclosed by the Russian government. Some Russian closed cities are open to foreign investment, but entry for foreigners requires a permit. An example of international cooperation in these cities is the Nuclear Cities Initiative (NCI), a joint effort of the United States National Nuclear Security Administration and Minatom, which involves, in part, the cities of Sarov, Snezhinsk, and Zheleznogorsk. The number of closed cities has been significantly reduced since the mid-1990s. However, on 30 October 2001, foreign travel was restricted without exception in the northern cities of Norilsk, Talnakh, Kayerkan, Dudinka, and Igarka. Russian and Belarusian citizens visiting these cities are not required to have permits; however, local courts have been known to deport Belarusian citizens. The number of closed cities in Russia is defined by government decree. The reasons for restrictions vary. These cities include: Altai Krai Amur Oblast Arkhangelsk Oblast Astrakhan Oblast Republic of Bashkortostan Chelyabinsk Oblast Kamchatka Krai Kirov Oblast Krasnoyarsk Krai Moscow Oblast Murmansk Oblast Nizhny Novgorod Oblast Orenburg Oblast Penza Oblast Perm Krai Primorsky Krai Pskov Oblast Saratov Oblast Sverdlovsk Oblast Tomsk Oblast Tver Oblast Vladimir Oblast Zabaykalsky Krai

Restricted territories

There is a list of territories within Russia that do not have closed-city status but require special permits for foreigners to visit. The largest locality within such territory is the city of Norilsk.

Azerbaijan

Estonia

There were two closed cities in Estonia: Sillamäe and Paldiski. As with all the other industrial cities, their population was mainly Russian-speaking. Sillamäe was the site for a chemical factory that produced fuel rods and nuclear materials for the Soviet nuclear power plants and nuclear weapon facilities, while Paldiski was home to a Soviet Navy nuclear submarine training centre. Sillamäe was closed until Estonia regained its independence in 1991; Paldiski remained closed until 1994, when the last Russian warship left. Tartu, home to Raadi Airfield, was partially closed. Foreign academics could visit the University of Tartu, but had to sleep elsewhere.

Kazakhstan

Kyrgyzstan

Latvia

Moldova

Moldova has one partially closed city: the village of Cobasna (Rîbnița District), which is under the control of the unrecognized state of Transnistria internationally recognized as part of Moldova. The village, on the left bank of the Dniester river, contains a large Soviet-era ammunition depot guarded by Russian troops. Only the Transnistrian and Russian authorities have detailed information about this depot.

Ukraine

Ukraine had eighteen closed cities, including:

Other countries

Albania

During the period of communist rule in Albania, the towns of Çorovodë and Qyteti Stalin (now Kuçovë) were closed cities with a military airport, military industry and other critical war infrastructure.

Australia

China

Germany

Hong Kong

The Frontier Closed Area (FCA) is a restricted zone along the northern border of Hong Kong, serving as a buffer between the closed border and the rest of the territory. Access to this area requires a Closed Area Permit. From 1951 to 2012, the FCA encompassed an area of 28 square kilometres, containing numerous villages. Following several stages of reduction, by 2016, the border town of Sha Tau Kok remained as the sole settlement within the FCA.

South Korea

Within the Korean Demilitarized Zone between North Korea and South Korea are two "peace villages" (one maintained by each nation): Daeseong-dong (South) and (possibly) Kijŏng-dong (North). Access by non-residents to Daeseong-dong requires a military escort, while Kijŏng-dong is not accessible to visitors.

North Korea

The Yongbyon Nuclear Scientific Research Center sits within a closed city that occupies 24.8 square kilometers (9.6 sq mi). The classification of a city being closed or not closed is dubious in a North Korean context, as North Korean citizens generally need a permit if they wish to travel outside of their county, and further permits required for entry to Pyongyang, thus the whole nation could be considered closed.

Mexico

Saudi Arabia

South Africa

Sweden

United Kingdom

United States

Between 1957 and 1962, approximately one-third of the United States was closed to Soviet citizens. Only eight states were accessible in their entirety: Oregon, Wyoming, Utah, North Carolina, Arkansas, Vermont, Missouri, and Mississippi.

In popular culture

The 2020 film Tenet prominently features a fictional Soviet-era closed city in Siberia called Stalsk-12.