Guide No. 2
Using the US census for family history
How to search and read US federal census records from 1790 to 1950, why the 72-year rule kept the 1950 census closed until 2022, and what each decade can tell you.
Contents
If you research American families, you'll spend more time with the federal census than with any other record. It covers nearly everyone, it repeats every ten years, and each decade asked slightly different questions, so lining up several returns for the same family builds a surprisingly detailed picture.
The 72-year rule
Census answers are confidential when they're collected. Statistics are published right away, but the individual pages, with names and household details, stay closed for 72 years. The practice goes back to a 1952 agreement between the Census Bureau and the National Archives, and Congress wrote it into law in 1978.
That's why the most recent census open to the public is 1950. The National Archives released it on April 1, 2022, with a free online name index. The 1960 census will follow in 2032. If you're looking for someone born after 1950, the census can't help yet, and you'll need other records.
What survives, decade by decade
The National Archives holds the population schedules from 1790 through 1950, with one large gap.
| Census | What it adds for family historians |
|---|---|
| 1790-1840 | Only the head of household is named; everyone else is a tally by age and sex |
| 1850 | First census to name every free person, with age, sex, occupation and birthplace |
| 1860 | Similar to 1850, plus personal estate value |
| 1870 | First census after emancipation to name formerly enslaved people |
| 1880 | Relationship to head of household; birthplaces of each person's parents |
| 1890 | Mostly lost after a fire in 1921; only fragments survive |
| 1900 | Month and year of birth, years married, children born and living, year of immigration, citizenship |
| 1910 | Similar to 1900, plus whether a man was a Union or Confederate veteran |
| 1920 | Year of naturalization; mother tongue |
| 1930 | Age at first marriage, veteran status, whether the home had a radio |
| 1940 | Where each person lived in 1935, education, income; extra questions for two people per page |
| 1950 | Similar to 1940, with extra sample questions for some people on each page |
Two notes on the early years. In 1850 and 1860, enslaved people were counted on separate "slave schedules" that usually listed them by age and sex under the enslaver's name, without their own names. For African American families, 1870 is often the first census that names your ancestors. And the 1890 loss stings: most of the schedules were damaged in a fire in Washington in 1921 and later destroyed. A special 1890 schedule of Union veterans and their widows survives for many states, which partly fills the gap.
Where to search
You don't have to pay to search the census. The main routes:
- The National Archives' own 1950 census website, searchable by name and location.
- Free genealogy databases run by nonprofits and partner organizations, which index most years.
- Your public library. Many libraries provide in-library or remote access to commercial genealogy databases with a library card.
- National Archives research rooms, which offer free access to several databases on site.
The National Archives' census research page lists online options and explains ordering copies.
State censuses are a separate set of records worth knowing about. Many states took their own counts in years ending in 5, such as 1855, 1865 or 1925. They're held by state archives and libraries and can fill the ten-year gaps, including the missing 1890.
Search tips when a family won't appear
Indexes are made by people reading old handwriting, and names are often mangled. If a family doesn't show up:
- Search without a first name, using only the surname and a place.
- Try phonetic spellings and obvious misreadings: Kowalski as Kovalsky, Hughes as Hews, an L read as an S.
- Search for a child with an unusual first name instead of the parents.
- Widen the age range by five years either way. Ages are often off.
- Leave out the birthplace, or try the country rather than the town.
- Browse page by page through the neighborhood. If you know an address, the enumeration district (the area one enumerator covered) narrows the search to a few dozen pages.
Older indexes such as Soundex, a code that groups surnames by sound, were built for some census years to help with exactly this problem. The National Archives explains the Soundex system if you run into microfilm indexes that use it.
Reading a census page
Take time over every column. Some things that are easy to miss:
Line and sheet numbers
Record them. They're how you or anyone else will find the entry again.
The neighbors
Families moved together, married each other, and appear as witnesses on each other's records. Write down the households on either side. When you lose your own family, following a neighbor sometimes finds them.
The informant
Census takers spoke to whoever answered the door, sometimes a child or a neighbor. In 1940 the informant is marked on the page. Inconsistent ages and birthplaces across decades often come from different informants, not from anyone lying.
Immigration and citizenship columns
From 1900 to 1930, these give a year of arrival and citizenship status, often abbreviated: "Al" for alien, "Pa" for first papers filed, "Na" for naturalized. Those answers tell you to look for passenger lists and court naturalization records. See our where to look page for who holds them.
Marks and corrections
Crossed-out entries, tally marks and codes in the margins were usually added by clerks later. They're rarely about your family, but occasionally they correct a mistake on the line.
Line up the decades
The real value comes from comparing censuses. Make a simple table for each person: one row per census, with age, birthplace, occupation and household. Patterns jump out. A child who appears in 1900 and vanishes by 1910 may have died, married or gone to work elsewhere. A widow listed with a different surname may have remarried. An ancestor whose age only rises by eight years across a decade may have been shaving years off.
Ages and birthplaces that disagree aren't failures. They're clues, and recording each version with its source lets you weigh them later.
Beyond the population schedules
The census also produced other records. Mortality schedules from 1850 to 1880 list people who died in the year before the count, useful for deaths before statewide registration. Agricultural and manufacturing schedules describe farms and businesses. Indian census rolls, separate from the federal census, were taken on many reservations from the 1880s to the 1940s. Some of these are held by state archives rather than the National Archives.
After the census
The census gives you dates, places and family groups. It rarely gives exact birth dates or parents' names for adults. For those, follow up with vital records, church registers, newspapers and court records. Our guides to historical newspapers and libraries and archives are the natural next steps.