World War II in Europe, 1939–1945: Who Held What, Month by Month

From Prague to Potsdam

In March 1939 Germany destroyed what was left of Czecho-Slovakia: Bohemia and Moravia became a German protectorate and Slovakia a German client state. Six and a half years later, at Potsdam in August 1945, the victorious Allies divided Germany into zones of occupation and moved Poland's western border to the Oder–Neisse line. In between, nearly every border in Europe changed at least once.

This map shows those changes as control on the ground, in 58 snapshots. It separates sovereign states from annexations, occupation regimes, client states and partisan-held areas, and it follows the front lines, the encircled pockets and finally the 1945 zones of occupation. The frame covers Europe, North Africa and the Middle East, so the desert war and the campaigns in Iraq, Syria and Iran are part of the same picture.

1939–1940: Partitions and Blitzkrieg

Germany annexed the Memel Territory in March 1939 and Italy took Albania in April. After the Nazi–Soviet Pact, Germany invaded Poland on 1 September 1939 and the Soviet Union invaded from the east on 17 September. By early October Poland was partitioned, and western Poland was annexed to the Reich. Lithuania received Vilnius, and the Winter War with Finland ended in March 1940 with the Moscow Peace, under which Finland gave up Karelia.

In April 1940 Germany occupied Denmark and invaded Norway. On 10 May it attacked in the west: the Netherlands fell within days, the panzers broke through at Sedan and reached the Channel, and the Allies were evacuated from Dunkirk. Paris fell in June, and France was divided into a German-occupied zone and the Vichy state. In the same weeks the Soviet Union occupied the Baltic states and took Bessarabia and northern Bukovina from Romania, and the Second Vienna Award gave northern Transylvania to Hungary.

1941–1942: The Axis at Its Height

Italy's invasions of Egypt and Greece went badly: by early 1941 the Greeks had pushed into Albania and the British had reached El Agheila in Libya. Germany then stepped in. In April 1941 it invaded Yugoslavia and Greece, which were divided among Germany, Italy, Hungary and Bulgaria, with a new Independent State of Croatia. Rommel besieged Tobruk, Crete fell to German paratroopers, and the British fought in Iraq and Syria.

On 22 June 1941 Germany invaded the Soviet Union. The map follows Operation Barbarossa through the pockets at Minsk, Smolensk, Uman, Kiev and Vyazma–Bryansk, the blockade of Leningrad and the German advance to the gates of Moscow in December 1941. In 1942 the Germans drove into the Caucasus and reached Stalingrad, and Rommel took Tobruk and pushed into Egypt. The Axis high-water mark came in November 1942, the same month as the Allied landings in North Africa and the German occupation of Vichy France.

1943–1945: Retreat, Liberation and Occupation

The German Sixth Army surrendered at Stalingrad in February 1943, and the Axis armies in Tunisia surrendered in May. After Kursk and the Allied landings in Sicily, Mussolini was deposed and Italy surrendered in September 1943; Germany occupied the north and centre of Italy and set up the Italian Social Republic. Kiev was liberated in November 1943 and Leningrad relieved in January 1944.

1944 brought collapse on every front. Rome was liberated in June, the Allies landed in Normandy, and Operation Bagration destroyed the German centre in Belarus. In August Paris and Warsaw rose, Paris was liberated and Romania changed sides. Bulgaria and Finland left the Axis in September, and Belgrade, Athens and Riga were freed in October. After the Battle of the Bulge and the encirclement of Budapest, the Soviet Vistula–Oder offensive and the Allied crossing of the Rhine closed in on Germany from both sides. Berlin was encircled in April 1945, and Germany capitulated on 7–8 May 1945. The map ends with the zones of occupation and the Potsdam settlement of August 1945.

How to Read the Map

• Each state has its own colour. The German Reich is dark grey and the Soviet Union red.
• Occupied territory is shown as a pale tint of the occupier's colour, so German-occupied land is pale grey and Soviet-occupied land pale red.
• Client states such as Slovakia, Croatia and Vichy France have colours of their own. Partisan-held areas (Yugoslav, Soviet, Italian and Greek) are schematic.
• Markers show battles, sieges, treaties, uprisings, liberations and atrocities, such as the Katyn massacre of 1940.
• In 1945 the map switches to the Allied zones of occupation, ending with Germany divided at Potsdam.

How the Map Was Made

The base geometry is Natural Earth. Pre-war and annexation borders come from OpenHistoricalMap (CC0) dated boundaries and from treaty and decree texts. On the Eastern Front, front lines from 1941 to 1944 were traced from the German army's daily situation maps (OKH 'Lage Ost'), and the western campaigns from US Army Center of Military History histories and 12th Army Group situation maps. The research also drew on New Zealand, Australian and British official histories, Hungarian National Archives data for 1944–45, and the French IGN map of the 1940 demarcation line. Treaty and administrative lines are accurate to about 2–5 km; traced front lines to about 3–10 km, and 10–20 km in fast-moving phases.

Chronological Timeline

• March 1939 — Protectorate of Bohemia and Moravia; Slovak state; Memel annexed
• April 1939 — Italy takes Albania
• 1 September 1939 — Germany invades Poland
• 17 September 1939 — Soviet Union invades eastern Poland
• March 1940 — Moscow Peace ends the Winter War
• April–June 1940 — Denmark, Norway, the Low Countries and France fall
• June 1940 — Soviets occupy the Baltic states and Bessarabia
• August 1940 — Second Vienna Award: northern Transylvania to Hungary
• April 1941 — Germany invades Yugoslavia and Greece; Tobruk besieged
• 22 June 1941 — Operation Barbarossa begins
• September 1941 — Kiev encircled; Leningrad blockaded; Iran occupied
• December 1941 — Germans before Moscow
• November 1942 — Axis high-water mark; Operation Torch; Vichy France occupied
• February 1943 — German surrender at Stalingrad
• May 1943 — Axis surrender in Tunisia
• September 1943 — Italy surrenders
• January 1944 — Siege of Leningrad lifted
• June 1944 — Rome liberated; Normandy landings; Operation Bagration
• August 1944 — Paris liberated; Warsaw Uprising; Romania changes sides
• December 1944 — Battle of the Bulge; Budapest encircled
• January 1945 — Vistula–Oder offensive
• March 1945 — Allies cross the Rhine
• April 1945 — Vienna taken; Berlin encircled; link-up on the Elbe
• 7–8 May 1945 — Germany capitulates
• 2 August 1945 — Potsdam Agreement: Germany divided, Oder–Neisse line