The U.S. Census provides a look into the whereabouts of families at a specific point in time. It shows the individual households as well as the people who were part of each household. It can be a great way to reveal unknown information about your family.

The U.S. Census Bureau website provides many tools to look at demographics and various angles of the data. But if you're looking for details of a specific ancestor, the tips here may help.

What is the U.S. Census?

Every 10 years (since 1790), the U.S. Census Bureau identifies and counts everyone living in the country. The data is used for things like how many representatives an area has in the U.S. House of Representatives. The data is kept private for 72 years, and then released to the public.

So, for example, the 1940 census data was released in April 2012. The 1950 census data was released in April 2022. The 1970 census data will be released in April 2032.

It's also imporant to know that census data is open to the public and available for free. You can find the pages of census documents and download them for your own use. Some private websites have indexed the names and added value to the data, which allows them to charge you for that additional functionality. I'll talk about indexing here shortly. Just know that the original pages of the census are free.

How do the districts work?

Each county in the U.S. is split up into "enumeration districts" (ED). Each district is sized to include the number of households that is practical for one person (the enumerator) to cover during a census period.

For example, the 1950 census in Brown County, Wisonsin had 141 EDs. As an area grows the number of EDs changes.

What does the data look like?

Each page of a census looks like a modern-day spreadsheet, except that the information is handwritten by the enumerator. Each line on the sheet represents one person living in the household. Consider this image from one page of the 1930 census from the Town of Red River in Kewaunee County, Wisconsin:

As you look at the above image, the most obvious thing to note is that all of the information is hand-written by the enumerator, whose name is in the upper right corner. Therefore, it can sometimes be difficult to read.

Another important feature is that in each household, only the head of the household (usually the husband) has the last name listed. All other members of that same household are listed under him without their last name repeated. This makes it visually obvious how big each household is and it helps to differentiate one household from the next.

If you click on the above image, you'll see the full image of that page of the census, with my great grandparents' household along with the households of two of their sons highlighted in a red bracket. It's also important to know that these three households do not appear next to each other in the census because it's alphabetical and they have the same surname (that's not how it works). When they appear together like this, it means they were neighbors. You can kind of picture the enumerator going house to house, farm to farm, collecting the data.

How can one search the census?

Let me start by talking about "indexing". When a census is indexed, that means all of the names have been added to a database for easy searching. The U.S. Census Bureau has indexed the 1950 census, so if that's the year you're looking for, searching can be easy. Just visit this site and follow the prompts:

• 1950census.archives.gov

Using the above site, you can search for a specific person, find their ED, find the specific census page in that ED, and even download it, all in one shot.

If you're searching for earlier years, the government did not index those names. So you may need to visit a private company like Ancestry.com or FamilySearch.org. Both of those sites allow you to search for a name to find their census records.

Another way is to search manually. It's not as simple but it works. First, you have to find the census page images to look through. They are all classified first by state, then by county, then by EDs within each county. So you have to know which county to search. If you're looking for a specific ancestor, knowing where they lived is important. This is why it can take a long time to perform such a search. You may start searching in one county only to find that the family actually moved to a different county (or state) since the last census. Or you might get lucky and find them where you thought they were.

Consider these two examples:

• My great grandfather, Florian LeGrave, is shown in the 1930 census above. But in the 1940 census, he's listed in the household of his son Clifford. Fortunately it's the same county, so it's not too hard to figure out.
• If you know your ancestor lived in Brown County, Wisconsin but you don't know exactly what city or town, you'll need to search through 140 EDs, each one having up to 40 pages of census images.

So, once you have an idea of what county & state you want to search, I recommend starting with this web site:

• Unified Census ED Finder

That site allows you to select the year (at the top of the page), then the state and county. Based on your selction, it provides a list of EDs in that county. Select one and start searching through all of the pages in that ED. There are anywhere from 5 to 40 pages in each ED.

Note that the above site does not host the actual census images. Instead, it provides a link to a couple of other sites where you can view the images for free. For example, you can click a link to Ancestry.com and view the images there.

What will future census data look like?

The simple answer is that I don't know. I imagine that in the future the U.S. Census Bureau will release the data in some kind of digital format only. For the 2020 census, nobody came to my door. I completed all of the information on the U.S. Census Bureau website. So when that data is released in 2092, there will be no images with handwriting to release.

When I download the images, what's a good file naming convention?

Obviously you can name the images on your computer anything you want that makes sense to you. Various sites that offer the images for download use slightly different conventions. I've figured out a good convention that works well for me. Here are a couple of examples of census pages that I've downloaded:

1950_WI_ED-05-103_Brown-County_Green-Bay_p04_Crevier-William.jpg
1950_CA_ED-30-212_Orange-County_Santa-Ana_p02_Roehm-Cornish.jpg

Notice that each name has several pieces of data, all separated by the underscore character.

• year
• state
• ED
• county
• city
• page number
• family member's name

I included the letters "ED" and "County" and "p" (for the page number) just to make it easier to read. But obviously you could exclude those, or just name it with the name of your ancestor who is on that page. I also don't use any spaces in the filename; I use dashes instead. This makes it easier for me to share certain pages here on the web. So, just do what makes sense to you.

Last update: Sat, Jul 5, 2025