Question: Gau East Prussia was formed in 1933 in Nazi Germany initially as a district within the Free State of Prussia, in 1939, East Prussia expanded following the annexation of which location, that was defined by the Treaty of Versailles in 1920 and refers to the most northern part of the German province of East Prussia, when as Memelland it was put under the administration of the Council of Ambassadors?

Context articles: Gau Southern Hanover-Brunswick
Reichsgau Danzig-West Prussia
Lithuania Minor
Gau East Prussia
East Prussia
Klaipėda Region
Gauliga Ostpreußen
Gau Eastern Hanover
Gau March of Brandenburg
West Prussia

Gau Southern Hanover–Brunswick (German: Gau Südhannover–Braunschweig) was a regional district established in 1933 in Nazi Germany.
 Initially the gau was a territorial component of both the Free State of Prussia and the Free State of Brunswick from 1933 to 1935.
 However, after the German constituent states were abolished in 1935, the Gaus replaced them in their responsibilities.
 Gau Southern Hanover-Brunswick was dismantled after Germany's defeat in 1945.
 The territory after the war became part of Lower Saxony in West Germany.
The Reichsgau Danzig-West Prussia (German: "Reichsgau Danzig-Westpreussen" ) was a Nazi German province created on 8 October 1939 from annexed territory of the Free City of Danzig, the Greater Pomeranian Voivodship (Polish Corridor), and the "Regierungsbezirk" West Prussia of "Gau" East Prussia.
 Before 2 November 1939, the Reichsgau was called Reichsgau West Prussia.
 Though the name resembled the pre-1920 Prussian province of West Prussia, the territory was not identical.
 In contrast to the former Prussian province, the "Reichsgau" comprised the Bromberg (Bydgoszcz) region in the South and lacked the "Deutsch-Krone" (Wałcz) region in the West.
Lithuania Minor (Lithuanian: "Mažoji Lietuva" ; German: "Kleinlitauen" ; Polish: "Litwa Mniejsza" ; Russian: Máлая Литвá ) or Prussian Lithuania (Lithuanian: "Prūsų Lietuva" ; German: "Preußisch-Litauen" , Polish: "Litwa Pruska" ) is a historical ethnographic region of Prussia, later East Prussia in Germany, where Prussian Lithuanians or Lietuvininkai lived.
 Lithuania Minor enclosed the northern part of this province and got its name due to the territory's substantial Lithuanian-speaking population.
 Prior to the invasion of the Teutonic Knights in the 13th century, the main part of the territory later known as Lithuania Minor was inhabited by the tribes of Skalvians and Nadruvians.
 The land became depopulated to some extent during the warfare between Lithuania and the Order.
 The war ended with the Treaty of Melno and the land was resettled by Lithuanian newcomers, returning refugees, and the remaining indigenous Baltic peoples; the term Lithuania Minor appeared for the first time between 1517 and 1526.
 With the exception of the Klaipėda Region, which became a mandated territory of the League of Nations in 1920 by the Treaty of Versailles and was annexed to Lithuania from 1923 to 1939, the area was part of Prussia until 1945.
 Today a small portion of Lithuania Minor is within the borders of modern Lithuania and Poland while most of the territory is part of the Kaliningrad Oblast of Russia.
Gau East Prussia was formed in 1933 in Nazi Germany initially as a district within the Free State of Prussia.
 In 1935, Germany's constituent states were dissolved and the Gaus replaced the states and their responsibilities.
 In 1939, East Prussia expanded following the annexation of the Klaipėda Region from Lithuania and the occupation of Poland, while a sliver of territory from the gau was transferred to Reichsgau Danzig-West Prussia.
 After Germany's attack on the USSR, the Belarusian city of Hrodna (German: "Garten" ) also became part of the Gau.
East Prussia (German: "Ostpreußen" , ] ; Polish: "Prusy Wschodnie" ; Lithuanian: "Rytų Prūsija" ; Latin: "Borussia orientalis" ; Russian: Восточная Пруссия ) was a province of the Kingdom of Prussia from 1773 to 1829 and again from 1878 (with the Kingdom itself being part of the German Empire from 1871); it also briefly formed part of the Weimar Republic's Free State of Prussia until 1945.
 Its capital city was Königsberg (present-day Kaliningrad).
 East Prussia was the main part of the region of Prussia along the southeastern Baltic Coast.
The Klaipėda Region (Lithuanian: "Klaipėdos kraštas" ) or Memel Territory (German: "Memelland" or "Memelgebiet" ) was defined by the Treaty of Versailles in 1920 and refers to the most northern part of the German province of East Prussia, when as Memelland it was put under the administration of the Council of Ambassadors.
 The Memel Territory, together with the other parts severed from Germany, the Saar and Danzig, was to remain under the control of the League of Nations until a future day when the people of these regions would be allowed to vote on whether the land would return to Germany or not.
The Gauliga Ostpreußen was the highest football league in the Prussian province of East Prussia (German: Ostpreußen) and the Free City of Danzig from 1933 to 1945.
 Shortly after the formation of the league, the Nazis reorganised the administrative regions in Germany, and the "Gau" "East Prussia" the Prussian province.
 Danzig however did not became part of this "Gau", being integrated in the "Gau Danzig-West Prussia" in 1939 instead.
Gau Eastern Hanover (German: "Osthannover") was a regional district of the NSDAP established in 1925 in the north eastern part of the Prussian Province of Hanover, comprising the governorates of Stade and Lunenburg in their then boundaries.
 Initially the Gau was a mere regional Nazi party subsection, but with the growing subjection of all public administration to Nazi party influence after the Machtergreifung, the Gau usurped from 1933 to 1935 more and more the functions of the Provincial government and its superordinate Free State of Prussia.
 However, after the German constituent states were de facto abolished in 1935, the Gaue replaced them in their responsibilities.
 Gau East Hannover - like all Nazi party structures - was dismantled after Nazi Germany's defeat in 1945.
 In 1946 the Control Commission for Germany - British Element (CCG/BE) reconstituted the Province of Hanover as the State of Hanover and later the same year it merged with three smaller neighbouring reconstituted German states to form the new state of Lower Saxony within the British Zone of Occupation.
 The municipality of Amt Neuhaus was allocated to Mecklenburg-Vorpommern.
The Gau Mark Brandenburg was formed in 1933 initially under the name Gau Kurmark in Nazi Germany initially as a district within the Free State of Prussia.
 In 1935, Germany's constituent states were dissolved and the Gaus replaced the states and their responsibilities.
 In 1940, Kurmark was renamed Mark Brandenburg.
 The Gau was dissolved in 1945, following Allied Soviet occupation of the area and Germany's formal surrender in 1945.
 After the war, the territory of the former Gau became part of the state of Brandenburg in East Germany except one of beyond Oder-Neisse line, which was given to People's Republic of Poland.
 Most territories of it are divided between Germany's State of Brandenburg and Poland's Lubusz Voivodeship now.
The Province of West Prussia (German: "Provinz Westpreußen" ; Kashubian: "Zôpadné Prësë" ; Polish: "Prusy Zachodnie" ) was a province of the Kingdom of Prussia from 1773 to 1824 and again from 1878 (with the Kingdom itself being part of the German Empire from 1871); it also briefly formed part of the Weimar Republic's Free State of Prussia until 1919/20.
 It was created out of the earlier Polish province of Royal Prussia following the First Partition of Poland.
 In February 1920, following Germany's defeat in 1918, West Prussia was divided: the mainly Slavic-speaking central parts became the Pomeranian Voivodeship of the Second Polish Republic, also known as the Polish Corridor; the city of Danzig became the Free City of Danzig, a semi-autonomous city-state under the protection of the League of Nations; the remaining territory was retained by the Free State of Prussia/Weimar Republic, with the western parts being joined to what remained of the former Province of Posen to form the new Posen-West Prussia Province, and the eastern parts being joined to the Province of East Prussia as Regierungsbezirk West Prussia.
 The territory was included within Reichsgau Danzig-West Prussia 1939–45, after which it became part of Poland.