Estonian Soviet Socialist Republic

The Estonian Soviet Socialist Republic, or Estonian SSR or ESSR, was a republic of the Soviet Union. It was administered by and subordinated to the Government of the Soviet Union. 
The ESSR replaced the Republic of Estonia on 21 July 1940, after the invasion of Soviet troops on 17 June 1940. A puppet government backed by the Soviet Union, declared Estonia to be a Soviet state. The Estonian SSR was taken into the USSR on 9 August 1940. The independence of the Republic of Estonia was reestablished on 20 August 1991.