In May 1939 a census, or Volkszählung, was conducted in Germany (including annexed Austria and the Sudetenland) that required the head of each household to fill out a supplementary card, or Ergänzungskarte, which mandated marking the Jewish background of each of the resident's four grandparents. By 1942, the cards of households with one or more residents with a Jewish grandparent marked on their card, the so-called "Minority Census," were collected and and sent to the Reich Genealogy Office (Reichssippenamt), then located in a building seized from the Berlin Jewish Community, where the cards most likely survived through the end of the war.

By the 1980s, the cards were in the custody of the State Archives of the German Democratic Republic in East Germany, and in the 1990s the cards were in the custody of the German Federal Archives. It was discovered that the cards are about 87% complete, lacking only for Thüringen, the Rhine Province, the districts of Erfurt and Minden, and several districts of Bavaria. Many of the districts included are areas that are now part of Poland (such as Silesia and Pomerania) and Russia (Königsberg / Kaliningrad).

Microfilm copies of of the supplementary cards of the German "Minority Census" of 1939 are publicly available in the United States at the Family History Library of Salt Lake City, Utah; the Leo Baeck Institute in New York and the United States Holocaust Memorial Museum in Washington, DC; In Germany, a computerized version is available on an application basis at the Federal Archives in Berlin-Lichterfelde, and a copy of the census is in Israel at Yad Vashem in Jerusalem.

The database contains the names of all of the people who lived in the household where one or more people in the household had a minimum of one Jewish grandparent. This means that there are also a number of non-Jewish individuals in the database, making it excellent source material for finding more biographical information on non-Jewish spouses. The specifics as to the racial/religious background of the individuals are not part of this database.

Currently, the searchable data includes persons who can be proven to have perished in the Holocaust, those who were born prior to 1903 (+110 years ago), and others who deceased prior to 1984 (+30 years ago).

Of the approximately 410,000 original entries, about 275,000 (or around 67%) of the "Minority Census" are available here online, searchable by family name, first name, maiden name if applicable, birth date, birth place, street address and city.

Tracing the Past is honored to have the opportunity to share this research tool online. Approximately two-thirds of the 170,000 Shoah victims from Germany are now searchable for the first time by residential street address.