Republics of the Soviet Union

The Republics of the Soviet Union, also known as the Union Republics, were the ethnically-based administrative regions of the former Soviet Union. For most of its history, the Soviet Union was a highly centralized state. However, during the 1980s, Soviet leader Mikhail Gorbachev made a series of reforms that were meant to decentralize the Soviet state. This, however, lead to the desolution of the Soviet Union in 1991.

Autonomous Soviet Socialist Republics
Some of the Union Republics, most notably Russia, were further subdivded into Autonomous Soviet Socialist Republics (ASSRs). Though also a part of thier respective Union Republics, the ASSRs were also established within ethnic and cultural lines.

Azerbaijan SSR

 * Nakhichevan ASSR, now the Nakhchivan Autonomous Republic

Georgian SSR

 * Abkhaz ASSR, now Abkhazia
 * Adjar ASSR, now Adjara

Russian SFSR

 * Bashkir ASSR, now the Republic of Bashkorostan
 * Buryat ASSR, now the Republic of Buryatia
 * Chechen–Ingush ASSR, now the Chechen Republic and the Republic of Ingushetia
 * Chuvash ASSR, now the Chuvash Republic
 * Dagestan ASSR, now the Republic of Dagestan
 * Kabardino-Balkar ASSR, now the Kabardino-Balkar Republic)
 * Kalmyk ASSR, now the Republic of Kalmykia
 * Karelian ASSR, now the Republic of Karelia
 * Komi ASSR, now the Komi Republic
 * Mari ASSR,now the Mari El Republic
 * Mordovian ASSR, now the Republic of Mordovia
 * North Ossetian ASSR now the Republic of North Ossetia–Alania
 * Tatar ASSR, now the Republic of Tatarstan
 * Tuvan ASSR,now the Tuva Republic)
 * Udmurt ASSR, now the Udmurt Republic)
 * Yakut ASSR, now the Sakha Republic

Former Russian ASSRs:
 * Crimean ASSR (October 18, 1921 – June 30, 1945; now the Republic of Crimea, territory disputed between Ukraine and Russia)
 * Kazak ASSR (1925–1936, now the independent state of Kazakhstan)
 * Kirghiz ASSR (1920–1925, became Kazak ASSR, now the independent state of Kazakhstan)
 * Kirghiz ASSR (1926–1936, became Kirghiz SSR, now the independent state of Kyrgyzstan)
 * Mountain ASSR (1922–1924, broken up into several smaller Northern Caucasus Republics)
 * Turkestan ASSR (1918–1924, now part of the independent states of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan)
 * Volga German ASSR (1918–1941)

Ukrainian SSR

 * Moldavian ASSR (1924–1940). In 1940, it was separated into Moldavian SSR (now the independent state of Moldova).
 * Crimean ASSR (February 12, 1991 – 1992). Crimea Oblast was promoted to the ASSR status following a referendum held on January 20, 1991 (now the Republic of Crimea, territory disputed between Ukraine and Russia)

Uzbek SSR

 * Karakalpak ASSR, now Karakalpakstan