Autonomous Republics of the Soviet Union

An Autonomous Soviet Socialist Republic (ASSR) of the Soviet Union (Russian: автономная советская социалистическая республика, АССР) was a type of administrative unit in the Soviet Union created for certain nations. The ASSRs had a status lower than the union republics of the Soviet Union, but higher than the autonomous oblasts and the autonomous okrugs.

In the Russian SFSR, for example, Chairmen of the Government of the ASSRs were officially members of the Government of the RSFSR. Unlike the union republics, the autonomous republics did not have a right to disaffiliate themselves from the Union. The level of political, administrative and cultural autonomy they enjoyed varied with time—it was most substantial in the 1920s (Korenizatsiya), the 1950s after the death of Joseph Stalin, and in the Leonid Brezhnev era.

The 1978 Constitution of the RSFSR recognized sixteen autonomous republics within the RSFSR. Their current status (as of October 2007) within the Russian Federation is given in parentheses:

Gorno-Altai Autonomous Oblast (now Altai Republic), Adyghe Autonomous Oblast (now Republic of Adygea), and Khakassian Autonomous Oblast (now Republic of Khakassia) were all promoted in status to that of an ASSR in 1991, in the last year of the Soviet Union. Only the Jewish Autonomous Oblast retained its autonomous oblast status in Russia.

...
Wikipedia