Pre-history

Before the October Revolution, the territory of modern Uzbekistan was divided between the Trans-Caspian, Samarkand, Syrdarya, and Ferghana regions of the Russian Empire, as well as between its vassal possessions—the Bukhara Emirate and the Khanate of Khiva. After the establishment of Soviet power in Turkestan in 1918, the territory of present-day Uzbekistan (except for the territories of the Bukhara Emirate and the Khiva Khanate) was merged into the Turkestan ASSR with a center set in Tashkent. In 1920, Soviet power was established in Bukhara and Khiva, which led to the Bukhara and Khorezm People's Republics being established. Later, the Khorezm People's Soviet Republic was transformed into Soviet Socialist Republic on October 30, 1923 followed by the establishment of the Bukhara People's Soviet Socialist Republic on September 19, 1924.^[4]

On September 16, 1924, an extraordinary session of the Central Electoral Commission of the Turkestan ASSR ruled to go forward with the national-state delimitation. This implied the establishment of the Uzbek SSR as part of the USSR. It comprised part of the lands of the former Samarkand, Semirechye and Ferghana Oblasts, as well as the Bukhara and Khorezm SSRs abolished at that time. This decision was put forward by the 2nd session of the All-Russian Central Executive Committee on October 14, 1924 and later approved by the 12th All-Russian Congress of Soviets on May 11, 1925. The date of foundation of the Uzbek SSR is considered October 27, 1924. Its center became Samarkand. Moreover, the Tajik Autonomous Soviet Socialist Republic was formed as part of the Uzbek SSR.^[5]

1924–1938

In 1925, oblasts were introduced in the Uzbek SSR. The oblasts were dividend into uyezds, and those, in turn, were divided into volosts. As of January 1, 1926, the administrative-territorial division of the Uzbek SSR were as follows:^[6]

However, oblasts and uyezds were abolished in the same year. Instead, they were converted into 10 okrugs: Andijan, Bukhara, Zeravshan, Kashka-Darya, Samarkand, Surkhan-Darya, Tashkent, Ferghana, Khodjent and Khorezm. The okrugs were further divided into rayons (analogous to districts).

In 1929, the Tajik Autonomous Soviet Socialist Republic and the Khodjent Okrug withdrew from the Uzbek SSR to become the Tajik SSR. This decision was approved by the CEC of the USSR on December 5, 1929.^[7]

In 1930, Tashkent became the capital of the Uzbek SSR. In the same year, all okrugs, as elsewhere in the Soviet Union, were abolished, and their constituent territories were transferred to the direct subordination of the soviet republic. In 1931, there were 71 rayons (districts) in the Uzbek SSR (which were divided into 1494 village councils) and 9 cities of republican subordination (which managed another 204 village councils).^[8]

In 1935, some of the rayons of the Uzbek SSR were merged into Kashka-Darya Okrug.

On December 5, 1936, the Kara-Kalpak ASSR was transferred to the Uzbek SSR from the RSFSR.^[9]

1938–1987

On January 15, 1938, the Uzbek SSR underwent again some transformations to comprise the newly established Bukhara (including Surkhan-Darya Okrug), Samarkand, Tashkent, Ferghana and Khorezm Oblasts.^[9]

According to data on October 1, 1938, the administrative-territorial division of Uzbekistan were as follows:^[10]

On March 6, 1941, Andijan and Namangan were taken off the Fergana Oblast to become separate regions, and the Surkhan-Darya Okrug was transformed into the Surkhan-Darya Oblast. On January 20, 1943 part of the Bukhara Oblast was withdrawn to enter a part of the Kashka-Darya Oblast.^[9] As a result, by January 1, 1947, the administrative-territorial division of the Uzbek SSR became as follows:^[11]

By a decree of the Presidium of the USSR Armed Forces dated February 13, 1956, part of the lands of the Hungry Desert and the Bostandyk (now Bostanlyk) district were taken from the Kazakh SSR and given to the Uzbek SSR. In 1963, a decree of the Presidium of the Supreme Soviet of the USSR also ruled that 36.6 thousand sq. km of underutilized lands of Chimkent and Kzyl-Orda belonging to Kazakh SSR be allocated to Uzbekistan.

On January 25, 1960, the Kashkadarya and Namangan Oblasts were abolished. The former became mostly part of the Surkhan-Darya Oblast, while the latter was distributed between Andijan and Ferghana Oblasts. Shortly thereafter, on February 16, 1963, a new Syrdarya Oblast was established from the parts of the newly acquired agricultural lands of Samarkand and Tashkent regions (the center originally set in Yangiyer, however starting from November 1963 in Gulistan).

On February 7, 1964 the Kashkadarya Oblast was restored followed by the Namangan Oblast on December 18, 1967.^[9]

On June 28, 1971 the Dzhetysay, Kirov and Pakhtaaral rayons of the Syrdarya Oblast of the Uzbek SSR that had very small areas were transferred from to the Chimkent Oblast of the Kazakh SSR.^[12]

On December 29, 1973 the Jizzakh Oblast was established from the part of the Syrdarya Oblast. Navoi was the last oblast to be established from the parts of the Bukhara and Samarkand oblasts on April 20, 1982. Consequently, as of January 1, 1987, the administrative-territorial division of the Uzbek SSR was as follows:^[9]

Post 1987

On September 6, 1988, the Jizzakh and Navoi oblasts were abolished. At the same time, the former was merged into the Syrdarya oblast, whereas the latter joined Samarkand. In May 1989, most of the former Navoi Oblast was transferred to the Bukhara Oblast. However, the Jizzakh Oblast was restored in February 1990 followed by the Navoi oblast in 1992.^[9]

After the Uzbek SSR became independent and turned into the Republic of Uzbekistan, the Karakalpak Autonomous Soviet Socialist Republic was renamed to the Republic of Karakalpakstan. Furthermore, oblasts were renamed into viloyats (English: regions), while rayons became tumans (English: district). In the early 1990s, a number of regions and cities of Uzbekistan that bore Soviet ideological names were renamed. The last (as of 2012) major change in the administrative-territorial division of Uzbekistan was the transfer of the Yangiabad District from the Syrdarya region to Jizzakh in 1999.