Polish areas annexed by the Soviet Union

Invasion of Poland (1939)

The Invasion of Poland, also known as the September Campaign or 1939 Defensive War in Poland and the Poland Campaign in Germany, was an invasion of Poland by Germany, the Soviet Union, and a small Slovak contingent that marked the start of World War II in Europe...

of Poland in 1939, which marked the beginning of World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, the Soviet Union

Soviet invasion of Poland (1939)

The 1939 Soviet invasion of Poland was a Soviet military operation that started without a formal declaration of war on 17 September 1939, during the early stages of World War II. Sixteen days after Nazi Germany invaded Poland from the west, the Soviet Union did so from the east...

invaded the eastern regions of the Second Polish Republic

Second Polish Republic

The Second Polish Republic, Second Commonwealth of Poland or interwar Poland refers to Poland between the two world wars; a period in Polish history in which Poland was restored as an independent state. Officially known as the Republic of Poland or the Commonwealth of Poland , the Polish state was...

, which Poles referred to as the "Kresy
Kresy
The Polish term Kresy refers to a land considered by Poles as historical eastern provinces of their country. Today, it makes western Ukraine, western Belarus, as well as eastern Lithuania, with such major cities, as Lviv, Vilnius, and Hrodna. This territory belonged to the Polish-Lithuanian...

," and annexed territories totaling 201,015 km² with a population of 13,299,000 inhabitants including Poles, Belorussians, Ukrainians, Jews, Czechs and others.

Most of these territories remained within the Soviet Union in 1945 as a consequence of Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

an-wide territorial rearrangements configured during the Tehran Conference

Tehran Conference

The Tehran Conference was the meeting of Joseph Stalin, Franklin D. Roosevelt and Winston Churchill between November 28 and December 1, 1943, most of which was held at the Soviet Embassy in Tehran, Iran. It was the first World War II conference amongst the Big Three in which Stalin was present...

of 1943. Poland was compensated for this territorial loss with the prewar German eastern territories much of which had been devastated during the war, and had been looted and pillaged by the Red Army. The Communist Poland

People's Republic of Poland

The People's Republic of Poland was the official name of Poland from 1952 to 1990. Although the Soviet Union took control of the country immediately after the liberation from Nazi Germany in 1944, the name of the state was not changed until eight years later...

described the territories as the "Recovered Territories
Recovered Territories
Recovered or Regained Territories was an official term used by the People's Republic of Poland to describe those parts of pre-war Germany that became part of Poland after World War II...

". The post-World War II territory of Poland was significantly smaller than the pre-1939 land areas, shrinking by some 77,000 square kilometers (roughly equaling that of the territories of Belgium

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

and the Netherlands

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

combined).

Molotov-Ribbentrop Pact

Early in the morning of August 24, 1939, the Soviet Union and Nazi Germany

Nazi Germany

Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...

signed a 10-year non-aggression pact, called the Molotov-Ribbentrop pact

Molotov-Ribbentrop Pact

The Molotov–Ribbentrop Pact, named after the Soviet foreign minister Vyacheslav Molotov and the German foreign minister Joachim von Ribbentrop, was an agreement officially titled the Treaty of Non-Aggression between Germany and the Soviet Union and signed in Moscow in the late hours of 23 August 1939...

. Most notably, the pact contained a secret protocol, revealed only after Germany's defeat in 1945, according to which the states of Northern

Northern Europe

Northern Europe is the northern part or region of Europe. Northern Europe typically refers to the seven countries in the northern part of the European subcontinent which includes Denmark, Estonia, Latvia, Lithuania, Norway, Finland and Sweden...

and Eastern Europe

Eastern Europe

Eastern Europe is the eastern part of Europe. The term has widely disparate geopolitical, geographical, cultural and socioeconomic readings, which makes it highly context-dependent and even volatile, and there are "almost as many definitions of Eastern Europe as there are scholars of the region"...

were divided into German and Soviet "spheres of influence". In the North, Finland

Finland

Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...

, Estonia

Estonia

Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...

and Latvia

Latvia

Latvia , officially the Republic of Latvia , is a country in the Baltic region of Northern Europe. It is bordered to the north by Estonia , to the south by Lithuania , to the east by the Russian Federation , to the southeast by Belarus and shares maritime borders to the west with Sweden...

were assigned to the Soviet sphere. Poland was to be partitioned in the event of its "political rearrangement"—the areas east of the Narev, Vistula

Vistula

The Vistula is the longest and the most important river in Poland, at 1,047 km in length. The watershed area of the Vistula is , of which lies within Poland ....

and San River

San River

The San is a river in southeastern Poland and western Ukraine, a tributary of the Vistula River, with a length of 433 km and a basin area of 16,861 km2...

s going to the Soviet Union while Germany would occupy the west. Lithuania

Lithuania

Lithuania , officially the Republic of Lithuania is a country in Northern Europe, the biggest of the three Baltic states. It is situated along the southeastern shore of the Baltic Sea, whereby to the west lie Sweden and Denmark...

, adjacent to East Prussia

East Prussia

East Prussia is the main part of the region of Prussia along the southeastern Baltic Coast from the 13th century to the end of World War II in May 1945. From 1772–1829 and 1878–1945, the Province of East Prussia was part of the German state of Prussia. The capital city was Königsberg.East Prussia...

, would be in the German sphere of influence, although a second secret protocol agreed in September 1939 assigned majority of Lithuania to the USSR. According to the secret protocol, Lithuania would retrieve its historical capital Vilnius

Vilnius

Vilnius is the capital of Lithuania, and its largest city, with a population of 560,190 as of 2010. It is the seat of the Vilnius city municipality and of the Vilnius district municipality. It is also the capital of Vilnius County...

, subjugated during the inter-war period by Poland

Second Polish Republic

Soviet occupation of Poland, 1939–1941

Under the terms of the Molotov-Ribbentrop Pact

Molotov-Ribbentrop Pact

, adjusted by agreement on 28 September 1939, two weeks after the German invasion of western Poland, the Soviet Union invaded the portions of eastern Poland assigned to it

Soviet invasion of Poland

Soviet invasion of Poland can refer to:* the second phase of the Polish-Soviet War of 1920 when Soviet armies marched on Warsaw, Poland* Soviet invasion of Poland of 1939 when Soviet Union allied with Nazi Germany attacked Second Polish Republic...

by the Molotov-Ribbentrop Pact, followed by co-ordination with German forces in Poland. The Soviets annexation included all Polish

Poland

Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

territory east of the line of the rivers Pisa

Pisa River

The Pisa is a river in north-eastern Poland with a length of 80.4 km. It belongs to the Masurian Lake District of the Warmian-Masurian Voivodeship. The Pisa river flows from Lake Roś near the town of Pisz, and is a tributary of the Narew, connecting the Lakeland region with the Vistula...

, Narew

Narew

The Narew River , in western Belarus and north-eastern Poland, is a left tributary of the Vistula river...

, Bug

Bug River

The Bug River is a left tributary of the Narew river flows from central Ukraine to the west, passing along the Ukraine-Polish and Polish-Belarusian border and into Poland, where it empties into the Narew river near Serock. The part between the lake and the Vistula River is sometimes referred to as...

, and San

San River

The San is a river in southeastern Poland and western Ukraine, a tributary of the Vistula River, with a length of 433 km and a basin area of 16,861 km2...

, except for western part of the Wilno Voivodship with its capital Wilno (Vilnius

Vilnius

), which was given to Lithuania

Lithuania

(see map), and the Suwałki region, which was annexed by Nazi Germany

Nazi Germany

.

The First draft of the Pact stipulated that Soviet gains in Poland would also cover the territory of the Lublin Voivodeship

Lublin Voivodeship (1919-1939)

Lublin Voivodeship was a unit of administrative division of the Second Polish Republic, in the years 1919–1939. Its capital and biggest city was Lublin.-Location and area:...

and eastern part of the Warsaw Voivodeship

Warsaw Voivodeship (1919-1939)

Warsaw Voivodeship was a voivodeship of Poland in the years 1919–1939. Its capital and biggest city was Warsaw.-Location and area:In the years 1919–1939, Warsaw Voivodeship covered north-central part of Poland, bordering East Prussia to the north, Pomorze Voivodeship and Łódź Voivodeship to the...

, and the Soviet-German demarcation line would reach the outskirts of Warsaw

Warsaw

Warsaw is the capital and largest city of Poland. It is located on the Vistula River, roughly from the Baltic Sea and from the Carpathian Mountains. Its population in 2010 was estimated at 1,716,855 residents with a greater metropolitan area of 2,631,902 residents, making Warsaw the 10th most...

(Lithuania

Lithuania

was to be occupied by the Germans). Therefore, the border of the spheres of interest of Germany and the USSR would run along the Pisa, Narew, Vistula

Vistula

The Vistula is the longest and the most important river in Poland, at 1,047 km in length. The watershed area of the Vistula is , of which lies within Poland ....

, and San rivers. This was changed, and the Germans were granted Lublin Voivodeship, while the Soviet sphere of interest included Lithuania.

Initially annexed by Poland in a series of wars between 1918 and 1921 (primarily the Polish-Soviet War

Polish-Soviet War

The Polish–Soviet War was an armed conflict between Soviet Russia and Soviet Ukraine and the Second Polish Republic and the Ukrainian People's Republic—four states in post–World War I Europe...

), these territories had mixed urban national populations with Poles

Poles

thumb|right|180px|The state flag of [[Poland]] as used by Polish government and diplomatic authoritiesThe Polish people, or Poles , are a nation indigenous to Poland. They are united by the Polish language, which belongs to the historical Lechitic subgroup of West Slavic languages of Central Europe...

and Ukrainians

Ukrainians

Ukrainians are an East Slavic ethnic group native to Ukraine, which is the sixth-largest nation in Europe. The Constitution of Ukraine applies the term 'Ukrainians' to all its citizens...

being the most numerous ethnic groups, with significant minorities of Belarusians

Belarusians

Belarusians ; are an East Slavic ethnic group who populate the majority of the Republic of Belarus. Introduced to the world as a new state in the early 1990s, the Republic of Belarus brought with it the notion of a re-emerging Belarusian ethnicity, drawn upon the lines of the Old Belarusian...

and Jews. Much of this rural territory had its own significant local non-Polish majority (Ukrainians in the south and Belarusians in the North).

The "need to protect" the Ukrainian and Belarusian majority populations was used as a pretext for Soviet invasion of Eastern Poland (including Western Ukraine and Belarus) carried out in the wake of Poland's dismemberment under the Nazi invasion with Warsaw being besieged and Poland's government being in the process of evacuation. The total area, including the area given to Lithuania, was 201,015 square kilometres, with a population of 13.299 million, of which 5.274 million were ethnic Poles and 1.109 million were Jews. An additional 138,000 ethnic Poles and 198,000 Jews fled the German occupied zone and became refugees in the Soviet occupied region

Stalin had decided in August 1939 that he was going to liquidate the Polish state, and a German-Soviet meeting in September addressed the future structure of the "Polish region." Soviet authorities immediately started a campaign of sovietization

Sovietization

Sovietization is term that may be used with two distinct meanings:*the adoption of a political system based on the model of soviets .*the adoption of a way of life and mentality modelled after the Soviet Union....

of the newly-acquired areas. The Soviets organized staged elections, the result of which was to become a legitimization of Soviet annexation of eastern Poland. Soviet authorities attempted to erase Polish history and culture, withdrew the Polish currency without exchanging roubles, collectivized

Collective farming

Collective farming and communal farming are types of agricultural production in which the holdings of several farmers are run as a joint enterprise...

agriculture, and nationalized and redistributed private and state-owned Polish property. Soviet authorities regarded service for the pre-war Polish state as a "crime against revolution" and "counter-revolutionary activity", and subsequently started arresting large numbers of Polish citizens. During the initial Soviet invasion of Poland, between 230,000 to 450,000 Poles were taken as prisoner, some of which were executed.

Polish prisoners of war in the Soviet Union (after 1939)

As a result of the Soviet invasion of Poland in 1939, hundreds of thousands of Polish soldiers became prisoners of war in the Soviet Union. Many of them were executed; over 20,000 Polish military personnel and civilians perished in the Katyn massacre....

NKVD officers conducted lengthy interrogations of the prisoners in camps that were, in effect, a selection process to determine who would be killed. On March 5, 1940, pursuant to a note to Stalin from Lavrenty Beria, the members of the Soviet Politburo

Politburo

Politburo , literally "Political Bureau [of the Central Committee]," is the executive committee for a number of communist political parties.-Marxist-Leninist states:...

(including Stalin) signed an order to execute 25,700 Polish POWs, labeled "nationalists and counterrevolutionaries", kept at camps and prisons in occupied western Ukraine

Ukraine

Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

and Belarus

Belarus

Belarus , officially the Republic of Belarus, is a landlocked country in Eastern Europe, bordered clockwise by Russia to the northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Its capital is Minsk; other major cities include Brest, Grodno , Gomel ,...

. This became known as the Katyn massacre

Katyn massacre

The Katyn massacre, also known as the Katyn Forest massacre , was a mass execution of Polish nationals carried out by the People's Commissariat for Internal Affairs , the Soviet secret police, in April and May 1940. The massacre was prompted by Lavrentiy Beria's proposal to execute all members of...

.

During 1939–1941 1.450 million.of the people inhabiting the region were deported by the Soviet regime, of whom 63.1% were Poles, and 7.4% were Jews. Previously it was believed that about 1.0 million Polish citizens died at the hands of the Soviets, however recently Polish historians, based mostly on queries in Soviet archives, estimate the number of deaths at about 350,000 people deported in 1939–1945.

Territories around Wilno (now Vilnius) annexed by Poland in 1920, were transferred to Lithuania

Lithuania

on a base of Lithuania-Soviet Union agreement (however Lithuania was soon annexed by Soviet Union to become the Lithuanian SSR

Lithuanian SSR

The Lithuanian Soviet Socialist Republic , also known as the Lithuanian SSR, was one of the republics that made up the former Soviet Union...

). Other northern territories were attached to Belastok Voblast

Belastok Voblast

Belastok Voblast or Belostok Oblast was a territorial unit in the Belarusian Soviet Socialist Republic from September 1939 to August 1945.- Administrative units :The administrative center of the voblast was the city of Belastok ....

, Hrodna Voblast

Hrodna Voblast

Hrodna Voblast or Grodno Oblast is a voblast in northwestern Belarus.The capital - Grodno is the biggest city of the province. It lies on the Neman River. Grodno's existence is attested to from 1127. Two castles dating from the 14th - 18th centuries are located here on the steep right bank of...

, Navahrudak Voblast

Navahrudak Voblast

Navahrudak Voblast or Novogrudak Oblast was a Voblast of the Byelorussian SSR following the annexation of West Belarus into the BSSR in 1939. The Voblast was formed on November 2, 1939, out of parts of the former Nowogródek Voivodeship in the Second Polish Republic.The Sovietisation of the...

(soon renamed to Baranavichy Voblast

Baranavichy Voblast

Baranavichy Oblast was a territorial unit in the Belarusian Soviet Socialist Republic created after the annexation of West Belarus into the BSSR in November 1939. The administrative centre of the province was the city of Baranavichy....

), Pinsk Voblast

Pinsk Voblast

Pinsk Voblast was a territorial unit in the Belarusian Soviet Socialist Republic created after the annexation of West Belarus into the BSSR in November 1939...

and Vileyka (later Maladzyechna) Voblast

Vileyka Voblast

Vileyka Voblast was a territorial unit in the Belarusian Soviet Socialist Republic created out of the eastern powiats of the Wilno Voivodeship after the annexation of West Belarus into the BSSR in November 1939. The administrative centre of the province was the city of Vileyka. The Voblast...

in Byelorussian SSR

Byelorussian SSR

The Byelorussian Soviet Socialist Republic was one of fifteen constituent republics of the Soviet Union. It was one of the four original founding members of the Soviet Union in 1922, together with the Ukrainian SSR, the Transcaucasian SFSR and the Russian Soviet Federative Socialist Republic...

. The territories to the south were transferred to the Ukrainian SSR

Ukrainian SSR

The Ukrainian Soviet Socialist Republic or in short, the Ukrainian SSR was a sovereign Soviet Socialist state and one of the fifteen constituent republics of the Soviet Union lasting from its inception in 1922 to the breakup in 1991...

: Drohobych Oblast

Drohobych Oblast

Drohobych Oblast , was an oblast in the Ukrainian SSR. It had a territory of 9.6 thousands of km³, and population of 853 thousand .-History:...

, Lviv Oblast

Lviv Oblast

Lviv Oblast is an oblast in western Ukraine. The administrative center of the oblast is the city of Lviv.-History:The oblast was created as part of the Ukrainian Soviet Socialist Republic on December 4, 1939...

, Rivne Oblast

Rivne Oblast

Rivne Oblast is an oblast of Ukraine. Its administrative center is Rivne. The area of the region is 20,100 km²; its population is 1.2 million...

, Stanislav (later known as Ivano-Frankivsk) Oblast

Ivano-Frankivsk Oblast

Ivano-Frankivsk Oblast is an oblast in western Ukraine. Its administrative center is the city of Ivano-Frankivsk. As is the case with most other oblasts of Ukraine this region has the same name as its administrative center – which was renamed by the Soviets after the Ukrainian writer, nationalist...

, Tarnopil Oblast

Ternopil Oblast

Ternopil Oblast is an oblast' of Ukraine. Its administrative center is Ternopil, through which flows the Seret River, a tributary of the Dnister.-Geography:...

and Volyn Oblast

Volyn Oblast

Volyn Oblast is an oblast in north-western Ukraine. Its administrative center is Lutsk. Kovel is the westernmost town and the last station in Ukraine of the rail line running from Kiev to Warsaw.-History:...

German occupation 1941–1944

These areas were conquered by Nazi Germany

Nazi Germany

in 1941 during Operation Barbarossa

Operation Barbarossa

Operation Barbarossa was the code name for Germany's invasion of the Soviet Union during World War II that began on 22 June 1941. Over 4.5 million troops of the Axis powers invaded the USSR along a front., the largest invasion in the history of warfare...

. The Nazis divided them up as follows:

Bezirk Białystok (district of Białystok), which included the Białystok, Bielsk Podlaski
Bielsk Podlaski
-Roads and Highways:Bielsk Podlaski is at the intersection of two National Road and a Voivodeship Road:* National Road 19 - Kuźnica Białystoka Border Crossing - Kuźnica - Białystok - Bielsk Podlaski - Siemiatycze - Międzyrzec Podlaski - Kock - Lubartów - Lublin - Kraśnik - Janów Lubelski - Nisko...

, Grajewo
Grajewo
Grajewo , is a town in north-eastern Poland with 23,302 inhabitants .It is situated in the Podlaskie Voivodeship ; previously, it was in Łomża Voivodeship...

, Łomża, Sokółka, Vaukavysk
Vaukavysk
Vawkavysk or Vaŭkavysk or Volkovysk is a town in the Hrodna Province of Belarus. It is the center of Vaŭkavysk district and has a population of around 48,000....

, and Hrodna
Hrodna
Grodno or Hrodna , is a city in Belarus. It is located on the Neman River , close to the borders of Poland and Lithuania . It has 327,540 inhabitants...

counties and was "attached to" (not incorporated into) East Prussia
East Prussia
East Prussia is the main part of the region of Prussia along the southeastern Baltic Coast from the 13th century to the end of World War II in May 1945. From 1772–1829 and 1878–1945, the Province of East Prussia was part of the German state of Prussia. The capital city was Königsberg.East Prussia...

;
Generalbezirk Litauen — the Vilna Province was incorporated into Lithuania
Lithuania
Lithuania , officially the Republic of Lithuania is a country in Northern Europe, the biggest of the three Baltic states. It is situated along the southeastern shore of the Baltic Sea, whereby to the west lie Sweden and Denmark...

, itself incorporated into the Reichskommissariat Ostland
Reichskommissariat Ostland
Reichskommissariat Ostland, literally "Reich Commissariat Eastland", was the civilian occupation regime established by Nazi Germany in the Baltic states and much of Belarus during World War II. It was also known as Reichskommissariat Baltenland initially...

;
Generalbezirk Weißruthenien — the Polish part of White Ruthenia (the western section of modern-day Belarus
Belarus
Belarus , officially the Republic of Belarus, is a landlocked country in Eastern Europe, bordered clockwise by Russia to the northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Its capital is Minsk; other major cities include Brest, Grodno , Gomel ,...

) was incorporated into the Reichskommissariat Ostland
Reichskommissariat Ostland
Reichskommissariat Ostland, literally "Reich Commissariat Eastland", was the civilian occupation regime established by Nazi Germany in the Baltic states and much of Belarus during World War II. It was also known as Reichskommissariat Baltenland initially...

;
Generalbezirk Wolhynien und Podolien — the Polish province of Volhynia
Volhynia
Volhynia, Volynia, or Volyn is a historic region in western Ukraine located between the rivers Prypiat and Southern Bug River, to the north of Galicia and Podolia; the region is named for the former city of Volyn or Velyn, said to have been located on the Southern Bug River, whose name may come...

, which was incorporated into the Reichskommissariat Ukraine
Reichskommissariat Ukraine
Reichskommissariat Ukraine , literally "Reich Commissariat of Ukraine", was the civilian occupation regime of much of German-occupied Ukraine during World War II. Between September 1941 and March 1944, the Reichskommissariat was administered by Reichskommissar Erich Koch as a colony...

; and
District Galicia
District Galicia
The District of Galicia was an administrative unit of the General Government in Nazi-occupied Ukraine from 1941 to 1944 centered in Lemberg ....

, East Galicia, which was incorporated into the General Government
General Government
The General Government was an area of Second Republic of Poland under Nazi German rule during World War II; designated as a separate region of the Third Reich between 1939–1945...

and became its fifth district.

During 1943–1944 ethnic cleansing

Ethnic cleansing

Ethnic cleansing is a purposeful policy designed by one ethnic or religious group to remove by violent and terror-inspiring means the civilian population of another ethnic orreligious group from certain geographic areas....

operations took place in the Ukraine (commonly known as the Massacres of Poles in Volhynia

Massacres of Poles in Volhynia

The Massacres of Poles in Volhynia and Eastern Galicia were part of an ethnic cleansing operation carried out by the Ukrainian Insurgent Army West in the Nazi occupied regions of the Eastern Galicia , and UPA North in Volhynia , beginning in March 1943 and lasting until the end of...

) which brought about an estimated 100,000 deaths and an exodus of ethnic Poles from this territory.

The Polish and Jewish language population of the regions in 1939 totaled about 6.7 million. During the war, an estimated 2 million persons perished (including 1.2 million Jews). These number are included with Polish war losses. 2 million (including 250,000 Jews) became refugees to Poland or the West, 1.5 million were in the territories returned to Poland in 1945 and 1.2 million remained in the USSR

Polish minority in the Soviet Union

The Polish minority in the Soviet Union refers to people of Polish descent who resided in the Soviet Union before its dissolution, and might remain in post-Soviet, sovereign countries as their significant minorities.-1917–1920:...

. Contemporary Russian historians also include the war losses of Poles and Jews from this region with Soviet war dead.

Soviet annexation

At the end of World War II

World War II

, the Soviet Union annexed most of the territories it had occupied in 1939, although territories with an area of 21,275 square kilometers with 1.5 million inhabitants were returned to Poland, notably the areas near Białystok and Przemyśl

Przemysl

Przemyśl is a city in south-eastern Poland with 66,756 inhabitants, as of June 2009. In 1999, it became part of the Podkarpackie Voivodeship; it was previously the capital of Przemyśl Voivodeship....

.

After the Soviet re-invasion of Poland in July 1944, the Polish government-in-exile prime minister flew to Moscow with Churchill to attempt to oppose annexations of its Molotov-Ribbentrop Pact portion of eastern Poland by the Soviet Union. He offered a smaller section of land, but Stalin declined, telling him that he would allow the exiled government to participate in the Polish Committee of National Liberation

Polish Committee of National Liberation

The Polish Committee of National Liberation , also known as the Lublin Committee, was a provisional government of Poland, officially proclaimed 21 July 1944 in Chełm under the direction of State National Council in opposition to the Polish government in exile...

. An agreement was reluctantly reached at the Yalta Conference

Yalta Conference

The Yalta Conference, sometimes called the Crimea Conference and codenamed the Argonaut Conference, held February 4–11, 1945, was the wartime meeting of the heads of government of the United States, the United Kingdom, and the Soviet Union, represented by President Franklin D...

where the Soviets would annex the entirety of their Molotov-Ribbentrop Pact portion of Eastern Poland, but would grant Poland part of Eastern Germany in return. Thereafter, eastern Poland was annexed into the Ukrainian Soviet Socialist Republic and the Byelorussian Soviet Socialist Republic.

On August 16, 1945 the communist dominated Polish government signed a treaty with the USSR to formally cede these territories. The total population of the territories annexed by the USSR, not including the portion returned to Poland in 1945, had an estimated population of 10,653,000 according to the 1931 Polish census. In 1939 this had increased to about 11.6 million. The composition by language group was Ukrainian

Ukrainian language

Ukrainian is a language of the East Slavic subgroup of the Slavic languages. It is the official state language of Ukraine. Written Ukrainian uses a variant of the Cyrillic alphabet....

37.1%, Polish

Polish language

Polish is a language of the Lechitic subgroup of West Slavic languages, used throughout Poland and by Polish minorities in other countries...

36,5%, Belarusian

Belarusian language

The Belarusian language , sometimes referred to as White Russian or White Ruthenian, is the language of the Belarusian people...

15.1%, Yiddish 8.3%, Other 3%. Religious affiliation: Eastern Orthodox 31.6%, Roman Catholic 30.1%, Ukrainian Greek Catholic Church

Ukrainian Greek Catholic Church

The Ukrainian Greek Catholic Church , Ukrainska Hreko-Katolytska Tserkva), is the largest Eastern Rite Catholic sui juris particular church in full communion with the Holy See, and is directly subject to the Pope...

26.7%, Jewish 9.9%, Other 1.7%.

From 1944 until 1952 the Ukrainian Insurgent Army were engaged in an armed struggle against the communists (in the early 1940s, the UIA, supported by local Ukrainian peasants, participated in the Ethnic cleansing operations

Massacres of Poles in Volhynia

). As a result of the skirmishes between the UIA and Soviet units, the Soviets deported 600,000 people from these territories and in the process 170,000 of the local population were killed in the fighting (See also Operation Vistula).