Lodz had the second largest Jewish population in prewar Poland, after Warsaw. German troops occupied Lodz in September 1939. In early February 1940, the Germans established a ghetto in Lodz and crowded more than 150,000 Jews into an area of about one and a half square miles. In 1941 and 1942 almost 40,000 Central European Jews and 5,000 Roma (Gypsies) were also forced into the ghetto. Between January and September 1942, over 75,000 ghetto residents were deported from Lodz to the Chelmno killing center. By the spring of 1944, the Lodz ghetto was the last remaining in German-occupied Poland. During that summer, the Germans deported the remaining Jews, most of them to Auschwitz.