Which One-Step Census Form Should I Use?
Stephen P. Morse, PhD   Joel D. Weintraub, PhD  David R. Kehs, PhD

Special Note for 1940

If you are interested in the 1940 Census in particular and you don't want to read everything here, you can go directly to one of the following One-Step tools.

1940 Unified Form
1940 Tutorial Quiz

and read the following paper for more details on searching in the 1940 census

Getting Ready for the 1940 Census: Searching without a Name Index

A. Overview

This project consists of various census tools.  There's a lot of overlap, and it's a bit confusing to know which tool to use when.  So below I will  briefly summarize each one and explain the differences between them.   You should also look at the 1940 Tutorial Quiz, -- it takes you through a series of questions to determine your particular situation and then suggests your best strategy for using the various tools.
But first let me mention that there are two ways of searching the census -- by name and by address.  Name searching is the easier one to do, and when it works you get instant gratification.  However, due to misspellings and other oddities, name searching doesn't always work.  And when it doesn't, you might need to resort to the more difficult address searching.  Items 1 through 4 below deal with address searching, and 5 through 6 with name searching.

1a. Obtaining EDs for the 1900 to 1940 Census -- Large Cities (1900-1940 Enumeration Districts Form)

Starting in 1880, all information in the census is arranged by ED and stored on microfilm rolls.  In order to know which microfilm roll to look in, you need to know the ED in which the person lived.

This One-Step tool allows you to determine the 1880, 1900, 1910, 1930, or 1940 ED number if you know the person's address.  It is a street-based search utility for large cities.  For 1880 it covers about 40 of the largest cities.  For 1900 and 1910 it covers the top 100 cities in population plus a few others.  For 1930 all cities having a population over 25,000 (over 400 cities) are included.  And for 1940 it includes all cities over 25,000, as well as a number of smaller ones, for a total of about 900 cities.  For 1920 cities, see 3 below.

We have resources to help individuals or societies add more cities to these utilities.  Please contact Joel Weintraub if interested.

1b. Finding ED Definitions (1880 to 1940 Enumeration District Definitions Form)
This One-Step tool provides a way to obtain definitions of EDs from the ED number and vice versa for the 1880 through 1940 censuses.  Location names are searchable within states.  This tool will be the main way of finding ED numbers for smaller communities in the years covered because it completely defines all EDs from rural areas, and smaller urban areas.

For the large cities, this is not as powerful as the every-street based tool (1a above).  In particular, our 1940 definitions do not show streets but instead includes only political definitions and institutional names.  If you want to see the streets within the specific EDs in these cities, you can use our 1900-1940 Census Street Finder.  For 1940, the ED definitions include a link (T1224, "view") to the National Archives film descriptions of each ED; for large cities you will be able to see the descriptions of each block within each ED.

If you use this ED Definions Form to find a 1930 ED number, you will also obtain links to convert it to a 1920 or 1940 ED number (see 3 below).  Similarly, if you use this ED Definitions form to find a 1920 or 1940 ED number, you will obtain links to convert to a 1930 ED number.

2. Obtaining Microfilm Rolls for all Census Years (Obtaining Microfilm Rolls Form)
Once you've found the ED number by using the previous tools, you'll want to view the images of the pages in that ED.  To do that you'll need to know the number of the microfilm roll that contains that ED and also how the EDs are arranged on that roll.

This One-Step tool allows you to determine the microfilm roll number and to see a layout of that roll.  Furthermore, if you have an ancestry.com subscription, this tool will let you view the images of the pages on that roll or in that ED.

3. Obtaining and/or Converting 1920-1930-1940 Census EDs (1920-1930-1940 ED Finder/Converter Form)
Obtaining EDs

Using this tool, you can specify a state and be presented with a list of cities, towns, and villages that have three or more EDs.  You can select the one you are interested in, and see a list of the 1920, 1930, or 1940 EDs for that area.  This is quick, but it is not as high a resolution as 1b above, which should be your first approach.

Converting EDs

Once you've found the ED number of a census, and perhaps the corresponding census record as well, you'll probably want to try finding the family in other census years.  This tool allows you to convert the ED number you've already found to the ED number that you'll need for the other year.  Of course this assumes the family you want hasn't moved during the intervening time period.

But more important, you can use this tool to obtain the 1920 ED from an address by first finding the 1930 ED, regardless of whether the family lived at that address in 1930 or not.  To do so you would use 1a or 1b to obtain the 1930 ED number of that address, and then use this tool to convert that to a 1920 ED number.  This is currently the only way to obtain 1920 EDs.

4. Viewing ED Maps for the 1940 Census (1940 ED Maps Tool)

For the first time, ED maps for counties and urban areas have been put online by the National Archives.  This tool will quickly identify those maps and provide links to them.  The maps can sometimes be useful for determining your ED number, especially in rural areas.

5. Census Search by Name ( Ancestry.com Search Form)
If you have an ancestry.com subscription, you will be able to search all the census years for a person by name (without knowing the address) and then view the image of that person's census page.  There are various forms on the ancestry website that allows you to do this search.

The tool presented here provides ancestry.com subscribers with an even more powerful search form than the one contained on the ancestry.com website.  You can search in ways that were not possible otherwise.

6. Alternate Census Search by Name (Genealogy.com Search Form)
If you have a genealogy.com subscription, you will be able to search various census years for a person by name (without knowing the address) and then view the image of that person's census page.  There are various forms on the genealogy website that allows you to do this search.

The tool presented here provides genealogy.com subscribers with the ability to search any year or state on the same form.  The genealogy.com website requires you to navigate to different pages for each state or year that you wish to search.

7. Free Census Search by Name (Familysearch.org Search Form)

You don't need a subscription to search by name using the familysearch.com website.  The tool presented here makes it even easier to search the data that is on the familysearch website.

B. Search Strategies: Using a Combination of One-Step Tools

The simplest way to find a person is to do a name search using my Ancestry.com (or Genealogy.com) Search Form.  If you are lucky enough to find the person and to view the corresponding image of the census page, you are done and have no need for my other forms.

However there are several things that might prevent you from being successful.  My other forms help with some of these problems, at least for the 1910, 1920, and 1930 census years.

One problem is that the name might be so illegible that it was not read correctly, and you will never find the person, no matter how creative you are in your use of the name search on my Ancestry.com (or Genealogy.com) Form.  In that case you will need to know the person's address, and then use my Enumeration District Form in conjunction with my Microfilm Roll Form to find the image of the census page.  These two forms are actually designed to work together -- when you find the ED number using my Enumeration District form, you can click on a button and will get to my Microfilm Rolls Form with the state and ED number prefilled for you.

Another problem is that the entire census page might have been skipped over when the names were transcribed.  An example of that (which ancestry.com eventually fixed) was the 1930 census, New York State, Kings County, ED 24-502.  Although the microfilm images for this ED were on the ancestry.com site and could be viewed with my Microfilm Rolls Form, no person in this ED could be found using my Ancestry.com Search Form.  So again you would have to use the other two forms.

You might be successful in finding the person using my Ancestry.com Search Form, but then you discover that there is no link to the image of the census page.  For some reason, that link was not displayed on the results page that ancestry.com provided.  But the results page does give the ED number in which the person lived, and even gives the page number within that ED.  With that information you can go to my Microfilm Roll Form and view the image of the census page.  So this is an example where my Ancestry.com Search Form was used in conjunction with my Microfilm Roll Form.

Next suppose that you already have a copy of the census page containing the person you want, but you can't find that person using my Ancestry.com Search Form.  It could be that the name was misspelled when it was transcribed into the database and you'd like to know how the transcriber thought it was spelled.  You can do that by looking at a text version of the census page.  To obtain such a text version, use my Ancestry.com Search Form but leave the name field blank.  Fill in the state, the ED number (including county), and the page.  Do the search and the result will be a text version listing everyone who is on that page.

Finally, suppose you were successful in finding the person you want in the 1930 census and now you want to find him in the 1920 census.  And you are not able to locate him with a name search for any of the reasons already mentioned.  You would like a 1920 Enumeration District Form, similar to my 1930 one.  Unfortunately we don't have that but we have the next best thing.  The 1920/1930 Enumeration District Converter lets you enter the 1930 ED and it gives you the corresponding 1920 one.  The 1930 Enumeration District Form is designed to work together with the 1920/1930 Enumeration District Converter -- when you find the ED number using the 1930 Enumeration District Form, you can click on a button and get to the 1920/1930 Enumeration District Converter with the 1930 ED value already prefilled for you.

If you are interested in 1940 specifically, use the 1940 Tutorial Quiz, which suggests a number of search strategies and second opinions for finding ED numbers.  Or use the 1940 Unified Form, which determines the search strategy automatically and displays the resulting EDs directly.

These were just a few examples.  Once you get familiar with this, you'll come up with strategies of your own.  Good luck with your searches.