Closed city

A closed city or closed town is a settlement where travel or residency restrictions are applied. Historically, the construction of closed cities became increasingly common in the Soviet Union during the Cold War. Since the dissolution of the Soviet Union in 1991, they remain widespread in Russia and some of the other post-Soviet countries. In modern Russia, closed cities are designated as "closed administrative–territorial formations".

Closed cities are sometimes represented only on classified maps that are not available to the general public.

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 kilometres (47 mi) 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 may be 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.

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.

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, Закры́тое администрати́вно-территориа́льное образова́ние (ЗАТО́)). Municipally, all such entities have the status of urban okrugs, as mandated by federal law.