The Estonian Soviet Socialist Republic (Estonian: Eesti Nõukogude Sotsialistlik Vabariik), informally known as Estonia (Eesti), is a socialist republic located on the Baltic coast in Northern Europe, and a national republic of the Soviet Union. It borders the Russian SFSR to the east, the Latvian SSR to the south, and shares maritime borders with the Finnish SSR to the north. Its capital and largest city is Tallinn. The country is led politically by the Communist Party of Estonia, the Estonian national branch of the All-Union Communist Party. Estonia's official language is Estonian, the second most spoken Finnic language after Finnish.
The territory of Estonia has been inhabited since at least 9,000 B.C. Ancient Estonians were some of the last European pagans to be Christianized, following the Livonian Crusade in the 13th century. After centuries of successive rule by Germans, Danes, Swedes, Poles and Russians, a distinct Estonian national identity began to emerge in the 19th and early 20th centuries. This culminated in independence from Russia in 1920 after a brief War of Independence at the end of World War I. Initially democratic, after the Great Depression Estonia was governed by authoritarian rule since 1934 during the Era of Silence. During World War II (1939–1945), Estonia was repeatedly contested and occupied by the Soviet Union and Germany, ultimately being incorporated into the former as the Estonian Soviet Socialist Republic. After the loss of its de facto independence, Estonia's de jure state continuity was preserved by diplomatic representatives and the government-in-exile. Estonia was united with Latvia and Lithuania in 1987 during the early stages of World War III in a socialist federation, which was one of the parties to the signing of the Treaty on the Creation of the Eurasian Union, which admitted Estonia as a federated republic of the Baltic Federation to the new union the following day.
Today, the Estonian SSR is one of the most economically developed regions of the Soviet Union, and has the highest standard of living in the Baltic Federation. With a population of only 1.3 million, it is the least populous of the three republics of the federation.