Making Sense of the U.S. Census

The U.S. Census, while not created for the purpose of genealogical research, is nevertheless one of the public records that genealogists find most helpful and tend to use most often. The amount of information that can be found or verified by finding a single family's census record is enormous. But how to harness this powerful tool?

Traditionally, using the census has involved using microfilms of the original handwritten pages, which were originally produced by the U.S. Government to preserve these records from decay. Many copies of the microfilms have been made, and genealogists usually go to either a Family History Center or to a regional office of the National Archives to view them and make photocopies.

Today, many census microfilm images are available online -- while this can speed up research considerably, not all censuses are available on microfilm. We'll cover both the traditional and electronic ways of using this great resource for that reason, but first a little history and explanation.

• What is the U.S. Census?
• How Is the Census Helpful to Genealogists?
• Let's Start -- How to Look Up an Ancestor
• What the Census Can Tell You About Your Family
• Find Them Faster Online

What Is the U.S. Census?

The U.S. Census was first taken in 1790, not long after the 13 colonies became the United States. Since the purpose of the census is to gather statistics for governmental planning, the scope of this decennial survey has gradually increased over the decades. For instance, the 1790 census recorded information in only six categories, and the head of household was the only person listed by name. By contrast, the long form of the 2000 census had 52 questions and was 12 pages long -- it asked the name of every person in the home and information about work status, disabilities, and the home itself, among other items.

One thing to keep in mind as you look through the census is that the actual records aren't released until 72 years after a census is taken, for privacy reasons. Right now, the most recent year available for research is 1930, so you will need to be able to trace your family back that far for it to be of use to you.

How Is the Census Helpful to Genealogists?

The main point of genealogy is establishing relationships between family members and providing documentation of those relationships. To varying degrees, the U.S. Census documents individuals and families by placing them in a particular location and listing their relationship to the head of household. The older censuses (pre-1850) are somewhat less useful because they list household members by category (i.e. "Males under 5 years of age") and not by name.

Starting with the 1850 census, however, the census taker was required to list every member of the household by name and record his or her age and birthplace. This level of detail is a genealogical gold mine, because if you have identified a person in the census as your ancestor, you can see a snapshot of the entire family in a specific place at one time. And if you think you've found an ancestor but aren't sure, the information listed about other family members can help you verify that you have the right person. Also, when you think you've found an ancestor at a specific location and time, you can search for other types of records in that location and time, such as birth, death, or marriage records. This will further help you verify whether or not you've located the right family in the census.

The 1900 census was the first to ask for immigration and naturalization information. This means that if your ancestors came to the United States around the turn of the century, you may be able to determine from their records where they came from, if you don't already know. If they resided in a port city at that time, you may want to try looking up passenger and immigration lists from that port to find out more about their journey.

Let's Start -- How to Look up an Ancestor

With all of this in mind, how do you actually go about finding your ancestors in the census? There are three main ways, all of which involve some type of index to show you which roll of microfilm has the correct record -- Soundex, book indexes, and electronic indexes. We'll take a brief look at each.

Using a Soundex Index

Soundex is a system for classifying names based on the sounds within them rather than strictly on spelling. It assigns a number to each consonant in the alphabet, and then gives each name a code based on the first letter and the numbers of the first 3 consonants in the name (see how it works). The end result is that names that are pronounced similarly are grouped together, like Smith and Smythe.

Soundex indexes exist for the 1880, 1900, 1910, and 1920 censuses -- they are grouped by state, sorted by the Soundex code, and then alphabetically by surname and first name. Some are only partial however. From the sample card below, you can see that it not only provides the very basic census information, but also gives you the volume, sheet, enumeration district (E.D.), and line where you can find the full record. You can use this information to select the right microfilm roll.