In September 1939 the Poznań and Pomorze Armies, fighting the Battle of the Bzura, also known as the Battle of Kutno, were concentrated around Kutno. The district was then incorporated into the Wartheland. On 16 June 1940 the Germans moved Kutno's Jews into a ghetto in the disused Konstancja sugar factory, where 7,000–8,000 people were crammed together. In the spring of 1942 the ghetto was liquidated and more than 6,000 people were deported to the Chełmno extermination camp on the Ner.