The Nazi German invasion of Poland in 1939 was a disastrous period for the town. Almost 80% of buildings were destroyed in air attacks and artillery bombardments. Houses around the market square and the local synagogue were burned. German occupiers carried out numerous mass executions of underground resistance fighters (from Home Army to Bataliony Chłopskie). At the beginning of 1941, the Nazi German administration established a ghetto in the southern part of Zwoleń for local Jews as well as all transports from neighbouring villages. In March 1941, Jews from Przytyk were transferred to Zwoleń (fact disputed by some scholars claiming that by then Jews of Przytyk were already removed). On December 22, 1941 the "Jüdischer Wohnbezirk" was formally registered. By April 1942, the unfenced, open ghetto had some 4,500 inhabitants living in 239 houses (7 per room on average). Hundreds were homeless. On August 19–20, 1942 approximately 5,000 Jews were shipped in from Gniewoszów ghetto nearby. The Germans also brought to the ghetto Jews from other locations (Janowice, Pionki, Jedlnia, Garbatka), further increasing their numbers. It is estimated that prior to mass deportations there were 6,500–10,000 Jews living there (top estimate by historian Adam Rutkowski has also been disputed). The Zwoleń ghetto was liquidated on 29 September 1942. All inmates (about 8,000 according to Daniel Blatman) were made to walk to the railway station in Garbatka. A few hundred prisoners unable to walk were shot along the way. From there, all Jews were transported in freight trains to Treblinka extermination camp where they were immediately gassed.