The subordinate entity of the Russian Federation, one of the 6 autonomous districts of Russia. It was liquidated after the enlargement of the regions in 2003-2008. Agin-Buryat AD was located in Eastern Siberia, in the southeast of Transbaikal. It was a subordinate entity of the Russian Federation and at the same time was a part of another entity (Chita Oblast). In 2008, it was merged with the Chita region in the Zabaykalsky Krai. After the unification, the Agin Buryat AD became a subordinate entity of the Zabaykalsky Krai with a special status.
The Agin-Buryat-Mongolian national okrug as part of the Chita Oblast was established in 1937 by a resolution of the Central Executive Committee of the USSR from Agin and Ulan-Onon aimags of the Buryat-Mongolian ASSR. In 1958 the Buryat-Mongolian Autonomous Soviet Socialist Republic was renamed into the Buryat Autonomous Soviet Socialist Republic., since 1977 - the Agin-Buryat Autonomous District.
The titular ethnic group in the district were the Buryats. According to the 2002 census, they made up 62% of the district's population. The Buryats differ from the titular nation of the country in language and religion. The Buryat language belongs to the northern group of Mongolian languages. Since the end of the XVI century, the Tibetan Buddhism of the Gelug school was widely spread among the Buryats. There are also traditional beliefs, which are termed Shamanism or Tengrism.