Lithuania, formally the Republic of Lithuania (Lithuanian: Lietuvos Respublika), is a European nation located in the Baltic area. It is one of three Baltic nations and is located on the Baltic Sea's eastern coast. Lithuania is bordered to the north by Latvia, to the east and south by Belarus, to the south by Poland, and to the southwest by Russia's Kaliningrad Oblast. It has a maritime boundary with Sweden on the Baltic Sea to the west. Lithuania has a population of 2.8 million people and an area of 65,300 km2 (25,200 sq mi). Vilnius is the capital and biggest city; other notable cities include Kaunas and Klaipeda. Lithuanians are part of the Balt ethnolinguistic group and speak Lithuanian, one of just a few extant Baltic languages.
For millennia, several Baltic tribes occupied the Baltic Sea's southeastern coastlines. Mindaugas consolidated Lithuanian regions in the 1230s before becoming king and establishing the Kingdom of Lithuania on July 6, 1253. The Grand Duchy of Lithuania was the biggest nation in Europe in the 14th century, including modern-day Lithuania, Belarus, Ukraine, and portions of Poland and Russia. With the marriage of the Polish queen Hedwig and Lithuania's Grand Duke Jogaila in 1386, the Crown of the Kingdom of Poland and the Grand Duchy of Lithuania were in a de facto personal union, and Wadysaw II Jagieo of Poland was anointed King jure uxoris. The Union of Lublin founded the Commonwealth of Poland and Lithuania in July 1569. The Commonwealth lasted more than two centuries until it was destroyed by neighboring nations in 1772–1795, with the Russian Empire annexing the majority of Lithuania's territory. On the eve of World War I's conclusion, Lithuania's Act of Independence was signed on February 16, 1918, establishing the modern Republic of Lithuania. During WWII, Lithuania was controlled by both the Soviet Union and Nazi Germany. When the Germans were withdrawing at the conclusion of the war in 1944, the Soviet Union reoccupied Lithuania. Armed resistance to Soviet occupation in Lithuania persisted until the early 1950s. Lithuania approved the Act of the Re-Establishment of the State of Lithuania on March 11, 1990, a year before the official fall of the Soviet Union, becoming the first Soviet country to declare its independence.
Lithuania is a developed nation with a high-income advanced economy that ranks well on the Human Development Index. It has high marks for civil rights, press freedom, internet freedom, democratic government, and peace. Lithuania is a member of the European Union, the Council of Europe, the eurozone, the Nordic Investment Bank, the Schengen Agreement, NATO, and the Organization for Economic Cooperation and Development. It is a member of the Nordic-Baltic Eight (NB8) regional cooperation arrangement and a Nordic Council permanent observer.