ABC7, AP The National Archives opened the vaults on the 1940 census Monday, releasing the family histories of the more than 21 million people still alive in the U.S. and Puerto Rico.
The census documents the tumultuous 1930s, which was transformed by the Great Depression and black migration from the rural South. Its survivors include celebrities Clint Eastwood and Morgan Freeman.
By law, personal census information is kept private for 72 years.
"Releasing census records is an odd event for us; we spend all our lives keeping the data we collect confidential," said Robert Groves, director of the U.S. Census Bureau. "However, once every 10 years, we work with the National Archives and Records Administration to release 72-year-old census records that illuminate our past. We know how valuable these records are to genealogists and think of their release as another way to serve the American public."
This is the first time census information will be made available online. With 3.9 million images scanned from more than 4,000 rolls of microfilm, the database represents the largest collection of digital information ever released by the Archives. It consists of individual responses to the survey that have been kept private for seven decades.
It took more than 70 people in the D.C. area years to convert the information from microfilm to digital.
The website -- 1940census.archives.gov -- includes a database of Americans living within the existing 48 states and six territories on April 2, 1940. The database can be searched by enumeration district. The National Archives has joined a consortium of groups to create a name-based index.
Robert Gates came to D.C. from his home in Georgia to witness the nation's history, and he said he's also excited for the opportunity to look at his family's history online.
"I wanna find out if people were actually married who said they were married, if there's any skeletons in the family closet," Gates said.
Delaware resident Karen Goyette said she plans to use the online archives to do some family fact-checking.
"I know where I think they lived and what they were doing. I think it'd be nice to check and see whether they were really in L.A., or were they really in Texas?" she said.
The census reveals some changes in the population. In 1940, 15 percent of adults were unemployed. Eight percent had a bachelor's degree, while currently, 28 percent of Americans hold one.