I'm adopted. I have non-identifying information about my birth mother and birth father, which I was able to use to find my birth mother's family through the 1940s census data (I also had her last name, which obviously helped). Unfortunately, she declined contact with me.

Now I want to find my birth father, but I do not have his last name. I do, however, know his family characteristics (father with approx. age, mother with approx. age, four siblings with approx. ages), and I have some idea of where they might have lived. I'd like to generate a list of possible families from the 1940s census and then narrow it down using the other non-identifying information I have (college degrees, marriages, etc.).

Right now, I'm going through census data manually on Ancestry.com (2400 records eyeballed so far, but no close matches). Does anyone know of a searchbot that will search these records for me and generate a list of possible families? Thanks so much for any help you can provide!

2 Answers 2


Ancestry.com and Familysearch.org will let you search census indexes using multiple family members' names, but I don't know of any sites that allow search by multiple family members' ages.

However, this Familysearch.org WILDCARD Search may shorten the list of families you need to eyeball.

Put in the Last Name: * a * (asterisk A asterisk, with no spaces) for the main person (preferably the youngest child living in 1940), and also for the Father's, Mother's, and Other Person's Last Name. This will give you a list of children who have two living parents and at least one more family member in the household, for all surnames which contain the letter A. You'll have to do this six times for A, E, I, O, U, and Y.

Fill in any known events for the main child. For this exercise I entered Birth Year Range: 1931-1932, Residence Place: Hamilton County, Ohio, Residence Year Range: 1940-1940.


You didn't say if you know the sex of the siblings. If so, after you fill in the parameters and click "SEARCH", scroll down to "FILTER YOUR RESULTS BY" and choose the GENDER.

Names like BAYER with multiple vowels will show up in multiple searches (A, E, Y).

This type of wildcard search will NOT work on Ancestry.com. They require at least three known letters in a name, in the correct order, and one of the three must be the first or last letter. Familysearch allows you to use only one, and it can be anywhere in the name. This also applies to first names, but they may have different rules for location names.

  • 1
    Thanks so much for the carefully thought-out advice. At first I was excited, thinking it would save me a bunch of time and allow me to search more records. But after trying it, it unfortunately doesn't help that much -- I still wind up with just as many records to look at manually (just sorted differently). What I really need is a search engine that allows multiple characteristics (gender, age) for multiple family members. I have genders and ages for all six family members at the time of the 1940 census, which would narrow it down considerably if I could search at once with everything I know.
    – Jeanne
    Commented Jul 5, 2016 at 13:26

Population Studies

The kind of search you want to do is theoretically possible -- see the user guides for the IPUMS USA website, especially the user guide chapter on Family Relationships. For an example of the kind of analysis population researchers do, see the 1940 Codebook.

The difficulty is getting the data set to work on. IPUMS and other sites designed to help people who are doing population studies are working from data samples, which by nature won't include a complete dataset.

The US Census Bureau offers software to use with their sample datasets, but the datasets available are for more modern censuses, and are focused on business and industry, not identifiable individuals.

Genealogy sites

As far as I can tell, most of the energy in the genealogy industry is focused on making it possible for customers to search for records they want by the names of the people listed inside. This means that if you don't know or can't guess the name of the person, it's difficult to get the search engines to spit the data out.

There are aids to searching the census on commercial sites, such as the One-Step Web Pages by Stephen P. Morse, but those pages take advantage of the existing search features which are set up to search by name, or by a limited set of indexed features.

See Searching the US Census by Name in One Step for the search form. One advantage of using Morse's search form over Ancestry's is that he indicates on the form which elements are in the index for different census years, so you can see at a glance if one data element is only indexed in a single census or in a limited range of years. Morse describes the many other advantages of using his forms instead of Ancestry's search forms in the FAQ.

Scroll down to the bottom of the page and look for Creating your own Search Applications and Viewers and you'll find his tools for writing your own One-Step applications.


In April 2012, the blog at Random Technology [RT] posted an alternate approach to searching the National Archive's census site, but I don't know if their software is still available for download. 1940’s census data API.

But the question remains -- no matter what tool you design -- where and how can you access the data? Without a fully-transcribed and indexed, computer-readable version of the census, it's difficult to have a computer search for the data you need.

  • Thanks, Jan. It looks like this is even more difficult than I expected it would be. I'll keep plugging away at it, though -- I have some hope that I'll find my birth father. I very much appreciate the excellent, detailed advice I've received here!
    – Jeanne
    Commented Jul 7, 2016 at 1:23

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.