If you’re looking for ancestors who were alive in 1940 in the United States, the census is one of the best resources available. The 1940 census has the most detailed information of all United States censuses that have been released so far. 1940 U.S. census data is also a fantastic starting place for building or extending your family tree.  

Let’s take a closer look at this census. (If you would like to learn more about censuses in general, see “U.S. Census Records.” 

Who Can You Find in the 1940 Census?

Are you searching for information about a grandparent, a great-grandparent, or another close relative? Your ancestors might be in the 1940 census if the following conditions apply:  

  1. They were alive at 12:01 a.m. on April 1, 1940, the official census date.i  
  2. They lived in one of the following places in the United States:
    1. The 48 existing states at the time 
    2. The District of Columbia 
    3. The following territories: 
      1. Alaska
      2. American Samoa
      3. Guam 
      4. Hawaii 
      5. The Panama Canal Zone 
      6. Puerto Rico 
      7. The Virgin Islands 
      8. An American consulateii 

Since the 1940 census was released to the public in 2012, it is possible that the 1940 census information about your relatives may not have been added to your family tree. Gather the information you already know about your ancestors who were alive in 1940, and get ready to start searching! 

How to Search 1940 Census Data

a migrant woman.

The 1940 U.S. census collection has been indexed and is available on most major genealogy sites, including FamilySearch.org.

On FamilySearch.org, you can use your relative’s name, sex, race, marital status, residence, and more to narrow your record results. In the 1940 U.S. census collection, you can even search according to where your ancestors lived in 1935. 

How to Read a 1940 Census Record 

To get the most from the 1940 census, it helps to understand the information it contains. When you first look at a census page, it might seem overwhelming! But we can break the page into five sections to make it easier to understand.

  • Section 1: Information about the family’s residence, including the street address, house number, and whether they owned or rented. 
  • Section 2: The person’s name and some personal information, such as age, marital status, birthplace, and citizenship. 
  • Section 3: The person’s residence information for 1935, five years prior to this census.  
  • Section 4: Detailed employment information, including occupation, industry, salary, and even length of unemployment prior to the census. 
  • Section 5: Additional information about two people on the census page, including parents’ birthplaces, native language, age at first marriage, and even whether the person had a Social Security number. 

What Are All the Codes on 1940 U.S. Census Records?

Some columns on the 1940 census included codes that may seem confusing. Explanations for most codes appear at the bottom of the census page, but you may find it easier to read the explanations on this National Archives page for the 1940 U.S. census.  

When you look at a 1940 census record, you might also notice that some column headings have letters instead of numbers. The columns with letters don’t contain unique information, but they may make it easier to read a record. If needed, you can use this handy tool to understand the codes in these columns.  

Clues That Are Unique to the 1940 Census

While most United States censuses contain the same basic information (name, age, marital status, and so forth), each census also offers unique information. These clues in 1940 census data may give additional insights about your ancestors: 

  • Who provided the information. In the 1940 U.S. census, a circled X appears next to the name of the person the census taker talked to in each household. If someone outside the home was the informant—for instance, a neighbor—that person’s name appears in the left margin.iii Knowing who the informant was can give you a clue to how accurate the information is. 
  • Residence in 1935. Knowing where someone lived in 1935 may help you find the same person in earlier census records or confirm that you have found the right family.
  • Employment Information. Employment information is much more detailed in the 1940 census than in earlier censuses. For example, people not currently working were asked if they were looking for work and even how long they had been out of work. You can feel a connection to your family by learning more about their employment situation.
  • Supplementary Questions. In this census, census takers were instructed to ask two people on each page some extra questions. (The two people were indicated by marks in the margin.) If your relative was asked extra questions, you get a wealth of additional information. For instance, the marriage information here can help you estimate a marriage year or notify you of multiple marriages. If you find a Social Security number in this section, you can look in Social Security records for more information.  

Read more about “Questions on the 1940 U.S. Census” on the FamilySearch blog. 

Try it Yourself

Want to practice using the 1940 census? Use the 1940 U.S. census collection on FamilySearch.org to try the following tasks. (Answers are below.) 

  1. Who gave the information for John W. Quibell’s household?  
  2. Philis Bowermaster was born in Ohio. Where did he live in 1935? 
  3. What is the relationship of Clifton R. Entwistle to his head of household? What was Clifton’s occupation and industry? 
  4. Margaret Esquibel was chosen to answer the supplementary questions. Was Margaret married more than once? How old was she at the time of her first marriage? (Hint: See columns 48 and 49.) 
  5. Choose some of your own family members who was alive in 1940 and locate them in the 1940 U.S. census. What were their occupations? Who was enumerated with your family members? If they were chosen to complete the supplementary questions, what else do you learn about them? 

The 1940 U.S. census is a wonderful tool for connecting with your family who lived in the United States. Use this census to gain a more complete picture of your family and extend your family lines.

More Information on the 1940 U.S. Census 

View U.S. Census Records on the Following Websites  

Records on FamilySearch.org are free to the public. Fees and other terms may apply for these other sites. 

Answers to TryItYourself Tasks 

  1. John’s wife Annie gave the information for the household. 
  2. In 1935, Philis Bowermaster lived in Jefferson County, Ohio. 
  3. Clifton R. Entwistle is listed as a brother of the head of household. He was listed as a clerk in the supreme court. 
  4. Margaret Esquibel was not married more than once. She was age 20 when she got married. 

Source: New on FamilySearch