The Klaipėda Revolt took place in January 1923 in the Klaipėda Region (also known as the Memel Territory or ). The region, located north of the Neman River, was detached from East Prussia, German Empire by the Treaty of Versailles and became a mandate of the League of Nations. It was placed under provisional French administration until a more permanent solution could be worked out. Lithuania wanted to unite with the region (part of Lithuania Minor) due to its large Lithuanian-speaking population of Prussian Lithuanians and major port of Klaipėda (Memel) – the only viable access to the Baltic Sea for Lithuania. As the Conference of Ambassadors favoured leaving the region as a free city, similar to the Free City of Danzig, the Lithuanians organized and staged a revolt.
Presented as an uprising of the local population, the revolt met little resistance from either the German police or the French troops. The rebels established a pro-Lithuanian administration, which petitioned to unite with Lithuania, citing the right of self-determination. The League of Nations accepted the fait accompli and the Klaipėda Region was transferred as an autonomous territory to the Republic of Lithuania on February 17, 1923. After prolonged negotiations, a formal international agreement, the Klaipėda Convention, was signed in May 1924. The convention formally acknowledged Lithuania's sovereignty in the region and outlined its extensive legislative, judicial, administrative, and financial autonomy. The region remained part of Lithuania until March 1939 when it was transferred to Nazi Germany after a German ultimatum.
Background
Lithuanian and Polish aspirations
The German–Lithuanian border had been stable since the Treaty of Melno in 1422. However, northern East Prussia had a significant Lithuanian-speaking population of Prussian Lithuanians or Lietuvninkai and was known as Lithuania Minor. The Klaipėda Region covered , which included the Curonian Lagoon of approximately . According to the Prussian Census of 1910, the city of Memel numbered 21,419 inhabitants, of whom 92% were German and 8% were Lithuanian, while the countryside was inhabited by a Lithuanian majority of 66%. In the Memel region as a whole, the Germans constituted 50.7% (71,191), the Lithuanians 47.9% (67,345), and the bilingual population (composed mostly of Lithuanians) – 1.4% (1,970). According to contemporary statistics by Fred Hermann Deu, 71,156 Germans and 67,259 Prussian Lithuanians lived in the region. The census that was carried out just after the revolt demonstrated slightly different results in 1925. It recorded the region's total population at 141,000. Declared language was used to classify the inhabitants, and on this basis 43.5% were German, 27.6% were Lithuanian, and 25.2% were "Klaipėdan" (Memeländisch) – those who spoke Lithuanian, but named themselves locals to distinguish from other Lithuanian population. Other sources give the interwar ethnic composition as 41.9% German, 27.1% Memeländisch, and 26.6% Lithuanian.
The idea of uniting Lithuania Minor with Lithuania surfaced during the Lithuanian National Revival of the late 19th century. It was part of the vision to consolidate all ethnic Lithuanian lands into an independent Lithuania. The activists also eyed Klaipėda (Memel), a major sea port in the Baltic Sea. It would become Lithuania's only deep-water access to the sea and having a port was seen as an economic necessity for self-sustainability. On November 30, 1918, twenty-four Prussian Lithuanian activists signed the Act of Tilsit, expressing their desire to unite Lithuania Minor with Lithuania. Based on these considerations, the Lithuanians petitioned the Allies to attach the whole of Lithuania Minor (not limited to Klaipėda Region) to Lithuania. However, at the time Lithuania was not officially recognized by the western powers and not invited into any post-war conferences. Lithuania was recognized by the United States in July 1922 and by most western powers in December 1922.