January — American troops cross the Siegfried Line into Belgium.
6 January — More than 80,000 Jews held captive by the Nazis are freed in Budapest, Hungary, by Russian soldiers.
12 January — World War II: The Soviet Union begins the Vistula-Oder Offensive in Eastern Europe against the Nazis
14 January — Eastern Germany is invaded by Russian troops.
18 January — 66,000 Jewish prisoners are evacuated from Auschwitz by the Nazis.
20 January — World War II: The Soviet Union occupies Warsaw.
20 January — The Holocaust: The evacuation of Auschwitz concentration camp begins.
27 January — The Holocaust: The Red Army liberates the Auschwitz and Birkenau death camps.
30 January — The Wilhelm Gustloff, with over 10,000 mainly civilian Germans from Gotenhafen (Gdynia) in the Gdansk Bay, is sunk by three torpedoes from the Soviet submarine S-13 in the Baltic Sea; up to 9,400 are thought to have died – the greatest loss of life in a single ship sinking in war action in history.