From the Wikipedia page 
The Republic of Karelia (Russian: Респу́блика Каре́лия, tr. Respublika Kareliya; IPA: [rʲɪˈspublʲɪkə kɐˈrʲelʲɪ(j)ə]; Karelian: Karjalan tazavalda; Finnish: Karjalan tasavalta; Veps: Karjalan Tazovaldkund) is a federal subject of Russia (a republic), located in the northwest of Russia. Its capital is the city of Petrozavodsk.
The modern Karelian Republic was founded as an autonomous republic within the Russian SFSR by the Resolution of the Presidium of the All-Russian Central Executive Committee (VTsIK) of June 27, 1923 and by the Decree of the VTsIK and the Council of People's Commissars of July 25, 1923 from the Karelian Labour Commune.
From 1940 to 1956, it was known as the Karelo-Finnish Soviet Socialist Republic, one of the union republics in the Soviet Union. In 1956, it was once again an autonomous republic and remains as part of Russia after the dissolution of the Soviet Union in 1991.