Stockton in the 1940s

Image from the LIFE photo archive

Oh, my.

I love the Census.

That every 10 years a country would undertake something so big and so audacious as to count every person - not venture a reasonable estimate, but count every person - just fascinates me. And the national stories - how we lived, where we worked - that emerge from all that information are every bit as compelling.

Census records are kept confidential for 72 years, after which they become public documents. And earlier this week, records from the 1940 count were made available online.

A 1940 Census form from what is now central Stockton 

 In 2010, when the most recent Census was taken, most of us mailed in forms that detailed the names and ages of people living in our households. But in 1940, Census workers canvassed the country in person, aiming to visit every house, apartment, trailer or tent where people might be living. That information was entered by hand into official record books.

It was a critical time - the country was emerging from the Great Depression, and about to head into the Second World War. Closer to home, a wave of migrants from the Great Plains were moving into the Central Valley - if you scan through San Joaquin County Census documents from 1940, you'll find lots of residents who reported living in Kansas, Nebraska, the Dakotas just a few years earlier.

Working with the documents is a little clunky - you can't search by name. Instead, records are organized by "enumeration districts," which are based on addresses.

Something that seems really special about this release is that many of the people who were counted in 1940 are still alive - perhaps your kids can find much younger versions of the grandparents and great-grandparents. (I've already spent a couple of hours looking for relatives, and when I finally spot their names - handwritten in beautiful 1940s cursive - it feels like the end of a treasure hunt).

It's also really interesting to see what your neighborhood was like back then. Did it even exist? In 1940, my house was still six years away from being built.