Ask a genealogist about her most used genealogy record, and nine times out of ten she’ll bring up census records. Federal censuses, taken every ten years since 1790, stand apart from other documents thanks to their consistency and coverage. In theory, they surveyed every home in the United States, and census questions provide data on nearly every individual. They’re available (often for free) on most genealogy websites, and indexes make them easy to search. And they play a unique role in genealogy research, allowing researchers to place an ancestor in a specific place and time, trace whole families and leap-frog back in time.
This table displays questions that have been asked during the census throughout time. An X indicates the corresponding census asked a question related to that subject.
|Category||Question/Subject||1790||1800||1810||1820||1830||1840||1850||1860||1870||1880||1890 (mostly destroyed)||1900||1910||1920||1930||1940|
|Names||Head of household's name only||x||x||x||x||x||x|
|All household members' names (except slaves)||x||x||x||x||x||x||x||x||x||x|
|Birth information||Age ranges of free white males||x||x||x||x||x||x|
|Age ranges of free white females||x||x||x||x||x||x|
|Ages of all household members||x||x||x||x||x||x||x||x||x||x|
|Month and year of birth||x|
|Parents' mother tongues||x||x|
|Marriage||Married in the census year||x||x||x||x||x|
|Age at first marriage||x|
|Immigration and citizenship||Number of aliens/non-naturalized residents||x||x||x|
|Year of immigration||x||x||x||x|
|Years in the United States||x||x|
|Attended school in past year||x||x||x||x||x||x||x||x||x||x||x|
|Can read or write||x||x||x||x||x||x||x||x||x||x|
|Other||Number of free colored||x||x||x|
|Relationship to head of household||x||x||x||x||x||x||x|
|Number of children mothered (total and living)||x||x||x|
|Able to speak English||x||x||x||x|
As you look through the table, you’ll notice a few trends. First, the variety of questions greatly increased after 1850. In fact, many consider 1850 the first census useful to genealogists; earlier censuses only asked questions about the head of household. In general, censuses have asked more questions throughout, making more-recent censuses more useful for genealogists. Note also that fire and flood destroyed most 1890 census records, making that year’s census useless for modern researchers. In addition, genealogists only have access to census records up to 1940. (For privacy reasons, the US government won’t release the 1950 census until 2022.)
If you need specific information about your ancestor, simply look at the above chart to determine which census might provide the answers you need. We have several articles on census records that can help you locate your ancestors in the census, plus overcome difficulties in finding them.
A version of this chart appears in the Family Tree Factbook. This portable, durable book contains hundreds of quick-reference genealogy strategies and statistics that will save time in your research. In addition to helpful charts like this one, you’ll find a roundup of the best genealogy websites, tips for researching documents like federal censuses, details about how to use DNA test results and more.