NEW YORK — The federal government plans to release intimate details about 132 million people in the United States who participated in the 1940 census when it makes the data available to the public on April 2 for the first time after 72 years of being kept confidential.
Access to the records will be free and open to anyone on the Internet — but they will not be immediately name searchable.
For genealogists and family historians, the 1940 census release is the most important disclosure of ancestral secrets in a decade and could shake the branches of many family trees. Scholars expect the records to help draw a more pointillistic portrait of a transformative decade in American life.
Researchers might be able to follow the movement of refugees from war-torn Europe in the latter half of the 1930s; sketch out in more detail where 100,000 Japanese Americans interned during World War II were living before they were removed; and more fully trace the decades-long migration of blacks from the rural South to cities.
More than 120,000 enumerators surveyed 132 million people for the Sixteenth Decennial Census — 21 million of whom are alive today in the United States and Puerto Rico, according to the U.S. Census Bureau.
The survey contained 34 questions directed at all households, plus 16 supplemental questions asked of 5 percent of the population. New questions reflected the government's intent on documenting the turbulent decade, by generating data on homelessness, migration, widespread unemployment, irregular salaries and fertility decline.
In a first for the National Archives and Records Administration, the nation's recordkeeper plans to post the entire census on the Internet — its biggest digitization effort to date.
That might be unsurprising given that increasingly popular online ancestry services make vast amounts of genealogical data available. In previous census releases, researchers had to crank through microfilm machines.