With a few key strokes at 6 a.m. Monday, a Silicon Valley engineer will open the lid on a treasure for genealogy buffs and local historians: the long-hidden personal records of 132 million Americans counted in the 1940 census.

And Nicka Smith will wake up at the crack of dawn, turn on her computer and scour the newly public online records from the National Archives. The Hayward resident is awaiting details about her father, uncle and grandmother to help document her family history.

"I've spent hours, probably years looking for people," said Smith, of the African American Genealogical Society of Northern California. "And the census is pretty much one of the hallmarks of genealogy research."

Kept confidential by law for 72 years, the raw data from the 1940 census records every home in the country: who lived there, what they did for a living and how much money they made, where they came from, their education, the wars they fought in. Statistical information from the 1940 tally was used to determine congressional seats in the 1940s, calculate population trends and gauge the effectiveness of New Deal economic programs.

More than one million people who fled West in the 1930s to escape rural poverty and the Dust Bowl were first counted in California in 1940.

"It really tracks what happened after the Great Depression," said Marcy Goldstein, director of the Bay Area branch of the National Archives. "It was a time of a lot of movement."

But to protect privacy, identifying details about each household were kept a state secret for an average American's life span -- then considered about 72 years.

Goldstein expects a crowd when the San Bruno archives open at 7:30 a.m. Monday, but maybe not as many people as when the 1930 census data came out in 2002. That's because now the data is entirely digitized and available to all online. A Silicon Valley-based federal contractor was to flip the switch Monday.

"We had people lining up around the block last time. We think people may try to log on at home this time," Goldstein said.

Among the first to scour and interpret 1940 data will be self-described "compulsive" genealogist Steve Morse, who keeps reams of family records at his Russian Hill home in San Francisco.

"I'm going for it because it's another document on my family. If it exists, I want to see it," said Morse, who doesn't expect any revelations -- other than his dad's 1940 salary. The average for a man was $956 a year.

Morse will be busy, however, as the founder and manager of one of the most popular free websites for people looking up their family records.

Even the National Archives and Records Administration sends confused genealogists to Morse, whose online database helps people track down buried census data based on where their families lived in 1940.

"It's a labor of love," said Morse, who invented a famous Intel microprocessor chip before taking an obsessive interest in cataloging his family's history.

Because the census records are indexed by location, sifting through them will challenge anyone who doesn't know exactly where their relatives lived. It will take many months for genealogical companies to index the records by name, but ardent genealogists and historians will find it themselves.

"A lot of us are really, really excited," said Lorie Garcia, Santa Clara's city historian.

Garcia said the records also are a boon for anyone who wants to know more about the old homes and neighborhoods where they live -- and the people who once called it home.

"Up until now, the record really stopped at 1930," Garcia said. "All you could find after that are deeds, the city directories, but they really don't tell you much about anybody. The census really tells you who people are. You're able to take the story one step further."

The 1940 census was the first to ask about income. Far more probing than 2010s census-takers, the 120,000 census workers who fanned out in spring 1940 asked women if they had been married more than once and how old they were at the time of their marriage. They asked veterans which wars they fought in. Choices included the Spanish-American War, Boxer Rebellion and the World War, which the census hadn't yet given a number.

"People were kind of grousing about the 10 questions they had to answer in 2010," Goldstein said.

In 1940, families had to answer 65 questions -- 34 for the population census and 31 for a separate housing census. A random selection of people -- about 5 percent of Americans -- had to answer 16 supplemental questions.

People may have been unhappy about it then, but to their ancestors the supplemental answers are a gold mine, Smith said.

"That's the beauty of the census," she said. "You don't know what's going to be on there until you look."

the 1940 census
How to use it
Want to find out more about your family's life in 1940? Or who lived in your home if it dates back to that time?
Go to 1940census.archives.gov to find it.
The newly released data will be difficult to sift through, especially for the first weeks and months before volunteers and genealogy companies catalog and index millions of documents by name.
Here are a few tips for doing it yourself:
Find out where your family lived in 1940. Without a street address, you can't find your "Enumeration District," or ED, and without an ED, you'll be hard-pressed to find anything useful in the 1940 census. But if you don't know the right location, other available documents may tell you.
Once you find a record for your family or street, you'll be able to post the scanned, handwritten document on Facebook or Twitter.
To get an ED, try:
  • The National Archives at San Francisco, 1000 Commodore Drive, in San Bruno. Archivists are on hand to help from 7:30 a.m. to 4:30 p.m. Monday.
  • Emailing the archivists at 1940census@nara.gov.
  • The Oakland Regional Family Research Center, 4766 Lincoln Ave., Oakland. The 75-computer genealogical center outside the Mormon temple is open from 10 a.m. to 9 p.m. Tuesday and Wednesday and 10 a.m. to 4 p.m. Thursday through Saturday. Phone 510-531-3905.
  • Steve Morse's website, www.stevemorse.org.
  • Your local library may also have free subscriptions to the leading genealogy company websites, which have indexed the 1930 census and other archives by a person's name and will do the same for the 1940 census over the coming months.
    Genealogy workshop at
    the National Archives
    When: 9 a.m. to 1 p.m.
    April 13
    Where: 1000 Commodore Dr., in San Bruno


    Online EXTRA
    Scan this code on a smartphone to view a gallery of newly released 1940-era photos from the U.S. Census Bureau or view it at http://photos.mercurynews.com. View Census Bureau videos from the time at www.census.gov/1940 census.
    Live chat: Join us online at www.mercurynews.com at noon today for a one-hour live chat with experts about the 1940 census and how you can discover details about your own family history. Featured guests are genealogist and computer engineer Stephen Morse of www.stevemorse.org, Nicka Smith of the African American Genealogical Society of Northern California, Ralph Severson of the Oakland Family History Center and Marcy Goldstein, director of the National Archives at San Francisco.