1940 Census Information and Tools

Here is some key basic information that will help you understand and research the 1940 Census. Click here to open 1940 Census Fast Facts.
Every name indexes recently have begun appearing online, for example at Familysearch.org (a free site) and Ancestry.com. You also can look for individuals by searching the Enumeration District where they lived. You'll find the 1940 Census images here. 
Here is NARA's 1940 Census information page, with more detailed general information, such as instructions to Enumerators, codes and meanings of some of the questions and answers, etc.
Here is the actual 1940 Census Enumeration Form.
This links to NARA's recommended steps for finding Enumeration Districts and starting research.  This includes links to search the Enumeration District Maps, which are available online.
You can use the Search Utilities at http://stevemorse.org/census/
These utilities are useful tools to search for 1940 EDs from addresses or locations as well as to convert a 1930 Census ED to a 1940 Census ED.  If you know someone's Enumeration District in 1930 and they haven't moved, your search for the 1940 ED is easy.
City Directories and World War II draft registration cards (available at Ancestry.com) are good resources for identifying addresses.
Other NARA online resources:
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Follow the 1940 Census on Twitter at hashtag #1940Census.