During the Cold War the Soviet Union created at least ten closed cities

Closed city

A closed city or closed town is a settlement with travel and residency restrictions in the Soviet Union and some of its successor countries. In modern Russia, such places are officially known as "closed administrative-territorial formations" ....

, known as Atomgrads, in which nuclear weapons-related research and development took place. After the dissolution of the Soviet Union, all of the cities changed their names (most of the original code-names were simply the oblast

Oblast

Oblast is a type of administrative division in Slavic countries, including some countries of the former Soviet Union. The word "oblast" is a loanword in English, but it is nevertheless often translated as "area", "zone", "province", or "region"...

 and a number). All are still legally "closed", though some have parts of them accessible to foreign visitors with special permits (Sarov, Snezhinsk, and Zheleznogorsk).

Cold War name	Current name	Oblast	Established	Primary function(s)
Arzamas-16	Sarov Sarov Sarov is a closed town in Nizhny Novgorod Oblast, Russia. Until 1995 it was known as Kremlyov ., while from 1946 to 1991 it was called Arzamas-16 . The town is off limits to foreigners as it is the Russian center for nuclear research. Population: -History:The history of the town can be divided...	Nizhny Novgorod Oblast Nizhny Novgorod Oblast Nizhny Novgorod Oblast is a federal subject of Russia . Its administrative center is the city of Nizhny Novgorod. Population: The oblast is crossed by the Volga River. Apart from Nizhny Novgorod's metropolitan area, the biggest city is Arzamas...	1946	Weapons design and research, warhead assembly
Sverdlovsk-44	Novouralsk Novouralsk Novouralsk is a closed town in Sverdlovsk Oblast, Russia. Population: The town, formerly known as Sverdlovsk-44, is situated on the eastern side of the Ural mountain range, about north of Yekaterinburg...	Sverdlovsk Oblast Sverdlovsk Oblast Sverdlovsk Oblast is a federal subject of Russia located in the Urals Federal District. Its administrative center is the city of Yekaterinburg formerly known as Sverdlovsk. Population: -Geography:...	1946	Uranium enrichment
Chelyabinsk-40 and later 65	Ozyorsk Ozyorsk, Chelyabinsk Oblast Ozyorsk or Ozersk is a closed town in Chelyabinsk Oblast, Russia. Population: It was founded on the shore of the Irtyash Lake in 1945...	Chelyabinsk Oblast	1947	Plutonium production, component manufacturing
Sverdlovsk-45	Lesnoy Lesnoy, Sverdlovsk Oblast Lesnoy is a closed town in Sverdlovsk Oblast, Russia, located north of Yekaterinburg on the banks of the Tura River. Population: -History:...	Sverdlovsk Oblast Sverdlovsk Oblast Sverdlovsk Oblast is a federal subject of Russia located in the Urals Federal District. Its administrative center is the city of Yekaterinburg formerly known as Sverdlovsk. Population: -Geography:...	1947	Uranium enrichment, warhead assembly
Tomsk-7	Seversk Seversk Seversk is a closed city in Tomsk Oblast, Russia, located northwest of Tomsk on the right bank of the Tom River. Population: Founded in 1949, it was known as Pyaty Pochtovy until 1954 and as Tomsk-7 until 1992. Town status was granted to it in 1956.The current Chair of the City Duma and Mayor...	Tomsk Oblast Tomsk Oblast Tomsk Oblast is a federal subject of Russia . It lies in the southeastern West Siberian Plain, in the southwest of the Siberian Federal District. Its administrative center is the city of Tomsk. Population:...	1949	Uranium enrichment, component manufacturing
Krasnoyarsk-26	Zheleznogorsk Zheleznogorsk, Krasnoyarsk Krai Zheleznogorsk is a closed town in Krasnoyarsk Krai, Russia, with a developed nuclear industry. It was formerly known as Krasnoyarsk-26. Population: -History:...	Krasnoyarsk Krai Krasnoyarsk Krai Krasnoyarsk Krai is a federal subject of Russia . It is the second largest federal subject after the Sakha Republic, and Russia's largest krai, occupying an area of , which is 13% of the country's total territory. The administrative center of the krai is the city of Krasnoyarsk...	1950	Plutonium production
Zlatoust-36	Tryokhgorny Tryokhgorny Tryokhgorny three mountains) is a closed town in Chelyabinsk Oblast, Russia, located in the western part of the oblast from Chelyabinsk. Population: It was founded in 1952, and was earlier known under the name Zlatoust-36 ....	Chelyabinsk Oblast	1952	Warhead assembly
Penza-19	Zarechny Zarechny, Sverdlovsk Oblast Zarechny is a town in Sverdlovsk Oblast, Russia, located on the Pyshma River east of Yekaterinburg. Population: It was granted urban-type settlement status in 1957; town status was granted in 1992....	Sverdlovsk Oblast Sverdlovsk Oblast Sverdlovsk Oblast is a federal subject of Russia located in the Urals Federal District. Its administrative center is the city of Yekaterinburg formerly known as Sverdlovsk. Population: -Geography:...	1955	Warhead assembly
Krasnoyarsk-45	Zelenogorsk Zelenogorsk, Krasnoyarsk Krai Zelenogorsk is a closed town in Krasnoyarsk Krai, Russia. It was formerly known as Krasnoyarsk-45 and was involved in enriching uranium for the Soviet nuclear program...	Krasnoyarsk Krai Krasnoyarsk Krai Krasnoyarsk Krai is a federal subject of Russia . It is the second largest federal subject after the Sakha Republic, and Russia's largest krai, occupying an area of , which is 13% of the country's total territory. The administrative center of the krai is the city of Krasnoyarsk...	1956	Uranium enrichment
Chelyabinsk-70	Snezhinsk Snezhinsk Snezhinsk is a closed town in Chelyabinsk Oblast, Russia. Population: It was founded in 1957, and was known as Chelyabinsk-70 until 1991...	Chelyabinsk Oblast	1957	Weapons design and research