Lithuania is a nation in Europe's Baltic region.[a] It is one of three Baltic states and is on the eastern coast of the Baltic Sea. Lithuania has land borders with Latvia to the north, Belarus to the east and south, Poland to the south, and Russia to the southwest[b]. It also has a maritime border on the Baltic Sea with Sweden to the west. Lithuania has a population of 2.8 million people and a land area of 65,300 km2 (25,200 sq mi). Vilnius is both its largest and capital city. Kaunas and Klaipda are two additional major cities. Lithuanian is one of the few still spoken Baltic languages and belongs to the Balt ethnolinguistic group.

Numerous Baltic tribes lived on the southeastern shores of the Baltic Sea for millennia. Mindaugas united the Lithuanian lands in the 1230s, becoming king and establishing the Kingdom of Lithuania on July 6, 1253. The present-day states of Lithuania, Belarus, the majority of Ukraine, and parts of Poland and Russia were all lands of the Grand Duchy of Lithuania in the 14th century.[19] With the marriage of Polish queen Hedwig and Lithuania's Grand Duke Jogaila, who was crowned King jure uxoris Wadysaw II Jagieo of Poland in 1386, the Crown of the Kingdom of Poland and the Grand Duchy of Lithuania were in a de facto personal union. In July 1569, the Union of Lublin established the Commonwealth of Poland and Lithuania. Between the years 1772 and 1795, when the Russian Empire annexed the majority of Lithuania's territory, neighboring nations dismantled the Commonwealth, which had existed for more than two centuries. On February 16, 1918, Lithuania's Act of Independence was signed, establishing the current Republic of Lithuania. Lithuania was occupied by both Nazi Germany and the Soviet Union during World War II. The Soviet Union reoccupied Lithuania as the Germans were retreating toward the war's conclusion in 1944. Up until the beginning of the 1950s, Lithuanian armed resistance to the Soviet occupation lasted. Lithuania became the first Soviet republic to declare independence when it passed the Act of the Re-Establishment of the State of Lithuania on March 11, 1990, a year before the formal dissolution of the Soviet Union.

Lithuania is a developed nation with an advanced economy and high incomes; performing exceptionally well on the Human Development Index. It receives high marks for its peacefulness, democratic governance, press freedom, and internet freedom. Lithuania is a member of NATO, the OECD, the Schengen Agreement, the Eurozone, the European Union, the Council of Europe, and the Nordic Investment Bank. Additionally, it is a member of the Nordic-Baltic Eight (NB8) model of regional cooperation.