The German army occupied Denmark on 9 April 1940. Until 1943, the occupation regime appeared relatively benign: It dominated foreign policy, but allowed the Danish government complete autonomy in domestic affairs, including control of the legal system and police forces. The tone of the German occupation changed in early 1943. Rather than yield to German demands, the Danish government resigned on 29 August 1943. German authorities took direct control of the Danish military and police forces. Other parts of the administration still remained in Danish hands. The German occupation of Denmark ended in May 1945.
Before the Second World War, Denmark had a total population of 3.85 million people. Approximately 6,500 of them were Jews. Their community consisted mostly of some 6,000 native Danes, while the rest were refugees from Central and Eastern Europe. Most Jews lived in Copenhagen, the country's capital and largest city. Considering the relatively small Jewish population and the support most Danes gave to their fellow Jewish citizens, Germany initially followed a general policy of non-interference regarding the “Jewish question”. After the implementation of martial law in August 1943, the order for the deportation of Danish Jews reached SS General Werner Best, the German civilian administrator in Denmark, on 28 September 1943. Approximately three weeks earlier, Best himself had taken the initiative to ask Berlin if the Jews in Denmark could be arrested. However, before the arrests could be carried out, the Danish authorities, Jewish community leaders, and countless private citizens mounted a massive operation to help Jews go into hiding or into temporary sanctuaries. When German police began to round-up Jews in Denmark on the night of 1 October 1943, they had little success. The Danish resistance, assisted by many ordinary Danish citizens, organised a partly coordinated, partly spontaneous rescue operation. Within less than a month, some 8,000 refugees, mostly people who were considered Jews and their non-Jewish relatives, escaped to neutral Sweden, which accepted the Danish refugees. Meanwhile, the Germans managed to deport 472 Jews, most of whom were refugees from Germany or Eastern Europe, to the Theresienstadt ghetto. Dozens of Danish Jews died there before the end of the war. In late April 1945, German authorities handed the Danish prisoners over to the Swedish Red Cross. Virtually all of the refugees returned to Denmark in 1945. In total, some 120 Danish Jews died during the Holocaust in Theresienstadt or during their escape from Denmark. One died in Auschwitz and one in Majdanek.
The Danish National Archives (Statens Arkiver) consist of: the Danish National Archive (Rigsarkivet) in Copenhagen (with records from the administration, primarily ministries, as well as some private archives which can have individual rules for access); the Danish National Business Archives (Erhvervsarkivet) in Aarhus (with records on trade and commerce in Denmark); the provincial archives (Landsarkivet) of Zealand (Sjælland), Lolland-Falster & Bornholm, which merged with the National Archive in 2012 (with records from local state and municipal agencies, as well as from private organisations and institutions in the region); similar regional records are held by the provincial archives of Funen (Landsarkivet for Fyn) in Odense, of Northern Jutland (Landsarkivet for Nordjylland) in Viborg and for Southern Jutland (Landsarkivet for Sønderjylland) in Aabenraa. In addition to the National Archives, there are also collections in private archives and museums.
EHRI has identified the Archives of Danish Occupation History 1940-1945 (Historisk Samling fra Besættelsestiden 1940-1945) as an important institution for Holocaust research. This institution keeps archives from the time of the German occupation of Denmark and from the time immediately before and after this period. There is an almost complete collection of Danish clandestine leaflets and books from the occupation period, which makes up the main part of the archives. Furthermore, there are the National Board of Industrial Injuries (Arbejdskadestyrelsen), the Mosaisk Troessamfunds arkiv (MT), a private archive in the National Archive (Rigsarkivet) with restricted access; the Museum of Danish Resistance 1940-1945 (Frihedsmuseet); the Danish-Jewish Museum (Dansk-jødisk museum); the Horseroed Museum (Horserødmuseet); and the Froeslev camp Museum (Frøslevlejrens museum). Outside of Denmark, EHRI has detected considerable Holocaust-relevant collections on Denmark at the United States Holocaust Memorial Museum, at Beit Terezin and, to a somewhat lesser extent, at Yad Vashem.