National delimitation in the Soviet Union in the context of "Soviet of Nationalities"

Tajikistan, officially the Republic of Tajikistan, is a landlocked country in Central Asia. Dushanbe is its capital and most populous city. Tajikistan borders Afghanistan to the south, Uzbekistan to the west, Kyrgyzstan to the north, and China to the east and is narrowly separated from Pakistan by Afghanistan's Wakhan Corridor. It has a population of more than 10.7 million people.

The territory was previously home to cultures of the Neolithic and the Bronze Age, including the Oxus civilisation in west, with the Indo-Iranians arriving during the Andronovo culture. Parts of country were part of the Sogdian and Bactrian civilisations, and was ruled by those including the Achaemenids, Alexander the Great, the Greco-Bactrians, the Kushans, the Kidarites and Hephthalites, the First Turkic Khaganate, the Umayyad and Abbasid Caliphates, the Samanid Empire, the Kara-Khanids, Seljuks, Khwarazmians, the Mongols, Timurids and Khanate of Bukhara. The region was later conquered by the Russian Empire, before becoming part of the Soviet Union. Within the Soviet Union, the country's borders were drawn when it was part of Uzbekistan as an autonomous republic before becoming a constituent republic of the Soviet Union on 5 December 1929.

Uzbekistan, officially the Republic of Uzbekistan, is a doubly landlocked country located in Central Asia. It is surrounded by five countries: Kazakhstan to the north, Kyrgyzstan to the northeast, Tajikistan to the southeast, Afghanistan to the south, and Turkmenistan to the southwest, making it one of only two doubly landlocked countries on Earth, the other being Liechtenstein. The country has a population of more than 37.6 million, making it the most populous country in Central Asia. Uzbekistan is a member of the Organization of Turkic States. Uzbek, spoken by the Uzbek people, is the official language and spoken by the majority of its inhabitants, while Russian and Tajik are significant minority languages. Islam is the predominant religion, and most Uzbeks are Sunni Muslims.

The first recorded settlers in the land of what is contemporary Uzbekistan were Eastern Iranian nomads, known as Scythians, who founded kingdoms in Khwarazm, Sogdiana, and Bactria in the 8th–6th centuries BC, as well as Fergana and Margiana in the 3rd century BC – 6th century AD. The area was incorporated into the Achaemenid Empire and, after a period of Greco-Bactrian rule and later by the Sasanian Empire, until the Muslim conquest of Persia in the seventh century. The early Muslim conquests and the subsequent Samanid Empire converted most of the people into adherents of Islam. During this period, cities began to grow rich from the Silk Road, and became a center of the Islamic Golden Age. The local Khwarazmian dynasty was destroyed by the Mongol invasion in the 13th century, leading to a dominance by Mongol peoples. Timur in the 14th century established the Timurid Empire. Its capital was Samarkand, which became a center of science under the rule of Ulugh Beg, giving birth to the Timurid Renaissance. The territories of the Timurid dynasty were conquered by Kipchak Shaybanids in the 16th century. Conquests by Emperor Babur towards the east led to the foundation of the Mughal Empire in India. Most of Central Asia was gradually incorporated into the Russian Empire during the 19th century, with Tashkent becoming the political center of Russian Turkestan. In 1924, national delimitation created the Uzbek Soviet Socialist Republic as a republic of the Soviet Union. It declared independence as the Republic of Uzbekistan in 1991.

In the Soviet Union, a Union Republic (Russian: Сою́зная Респу́блика, romanized: Soyúznaya Respúblika) or unofficially a Republic of the USSR was a constituent federated political entity with a system of government called a Soviet republic, which was officially defined in the 1977 constitution as "a sovereign Soviet socialist state which has united with the other Soviet republics to form the Union of Soviet Socialist Republics" and whose sovereignty is limited by membership in the Union. As a result of its status as a sovereign state, the Union Republic de jure had the right to enter into relations with foreign states, conclude treaties with them and exchange diplomatic and consular representatives and participate in the activities of international organizations (including membership in international organizations). The Union Republics were perceived as national-based administrative units of the Union of Soviet Socialist Republics (USSR).

The Soviet Union was formed in 1922 by a treaty between the Soviet republics of Byelorussia, Russian SFSR (RSFSR), Transcaucasian Federation, and Ukraine, by which they became its constituent republics of the Union of Soviet Socialist Republics (Soviet Union). For most of its history, the USSR was a one-party state led by the Communist Party of the Soviet Union. Key functions of the USSR were highly centralized in Moscow until its final years, despite its nominal structure as a federation of republics; the light decentralization reforms during the era of perestroika (reconstruction) and glasnost (voice-ness, as in freedom of speech) conducted by Mikhail Gorbachev as part of the Helsinki Accords are cited as one of the factors which led to the dissolution of the USSR in 1991 as a result of the Cold War and the creation of the Commonwealth of Independent States.

The Tajik Soviet Socialist Republic, also commonly known as Soviet Tajikistan, the Tajik SSR, TaSSR, or simply Tajikistan, was one of the constituent republics of the Soviet Union which existed from 1929 to 1991 in Central Asia.

The Tajik Republic was created on 5 December 1929 as a national entity for the Tajik people within the Soviet Union. It succeeded the Tajik Autonomous Soviet Socialist Republic (Tajik SSR), which had been created on 14 October 1924 as a part of the predominantly Turkic Uzbek SSR in the process of national delimitation in Soviet Central Asia. On 24 August 1990, the Tajik SSR declared sovereignty in its borders. The republic was renamed the Republic of Tajikistan on 31 August 1991 and declared its independence from the disintegrating Soviet Union on 9 September 1991; thus modern Tajikistan is its direct legal successor state.