When the 1940 U.S. census is released on April 2, 2012, there won't be any searchable indexes. Just millions of digitized pages of names (132.2 million names if you're wondering). Don't get me wrong - having them all released digitally and free by the National Archives is amazing! But to find my Granddad (aka Walter Henry Thomas) in the 1940 census, I'm going to need to do a little background research.
To locate your own ancestor or relative in the 1940 U.S. census you will first have to determine where they were living at the time. If they lived in a bigger city, then City Directories might be just the tool you need to pinpoint their 1940 address. If not, or city directories aren't available to you, then look for any records created by the family around that time for clues to their location. My grandfather, for example, applied for a copy of his birth certificate in May 1941, and received a letter from his local Representative William L. Shaffer (with details about the steps he would need to take to *correct* his birth certificate because his family had changed their name from Toman to Thomas in the intervening years) that included his address at the time - 606 Center Street, Wilkinsburg, Pennsylvania.
Wilkinsburg is a borough located in Allegheny County, PA, just outside of Pittsburgh. Now just because he was living there in 1941 doesn't mean he was at the same address in 1940. It wouldn't be unusual for a single man alone in the big city to move around from year to year, but at least it is a place to start. Using Google Maps I can pinpoint the location of 606 Center Street in Wilkinsburg. By cross-checking with historic maps from that time available online at Historic Pittsburgh, I can confirm that the relevant street names have not changed since 1940. So I now have an address....but that still isn't enough.
To locate individuals in the digitized 1940 census pages, you will need what is called an Enumeration District or ED. An Enumeration District, as defined by the U.S. Census Bureau, is a geographic area for which an individual enumerator could be expected to complete a count of the population within the allotted time for that particular census year. This could be an area as small as a single city block if that particular block was packed with duplexes and apartment buildings, or as large as several miles in width if the area was exceedingly rural. This might sound complicated, but it is actually really easy to learn what 1940 Enumeration District a particular address was located in thanks to the 1940 Census ED One-Step tools developed by Stephen P. Morse, PhD and Joel D. Weintraub, PhD.
Using the 1940 Census ED Finder Obtaining Large City 1940 EDs in One Step (available for all U.S. cities of 25,000+ in 1940, as well as many smaller ones), I set out to learn which ED I will need to be looking through for my Granddad on April 2, 2012. I would like to stop and say thank you here to the many volunteers who helped add new 1940 cities to the website, especially Judy Caine who helped with Pittsburgh among many others. Using this tool I entered the state of Pennsylvania, the city of Wilkinsburg, and the main street of Center, followed by the cross streets of Rebecca and Franklin, and the back street of Mill (basically the four streets that make up that city block). This simple step resulted in just a single ED to search - ED 2-615 (Allegheny County, Pennsylvania). Can it really be that easy?
Selecting the ED, brings up information extracted from the relevant NARA ED microfilm, including a list of the streets in Wilkinsburg (Allegheny Co), PA Enumeration District 2-615. You can select the "View Microfilm" button if you want to view the actual microfilm image as well.
If this just seems too easy, you can also double-check the result by viewing the 1940 Enumeration District maps online from the National Archives. Using their free Online Public Access tool, I searched directly for the ED number in which I'm interested - "ED PA 2-615," which brought up the series of 1940 census ED maps for Allegheny County. Alternatively, if I hadn't had Steve Morse's handy tool to learn the ED I could have spent a lot of time browsing through these graphic (non-searchable) maps to find the correct city/neighborhood and street. There's a Viewing 1940 Enumeration District Maps in One Step tool as well, although Wilkinsburg is lumped in with the rest of Pittsburgh here, just as it is on NARA's website. No matter how you choose to get to the maps, I only completed this exercise to show you this map of Wilkinsburg with my Granddad's location pinpointed, so you can see that the 1940 Census ED Finder seems to do its job well!
The ED designation will likely not take me to the correct page (only to the first page of that ED), but it will get me to the right neighborhood, so all I will have left to do is spend a little time browsing through census pages to find him, while learning about his neighborhood and neighbors along the way. Sounds like a lot of fun to me!