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Clues in Census Records, 1850-1950

Experienced genealogical researchers use clues found in one record to find other records about the same individual. This page describes some of the clues found in census records.  Please note that the accuracy of census information depends on the knowledge of the person providing the information to the enumerator.  In addition, most of the 1890 census was destroyed as a result of a fire in 1921

Date of birth

  • The 1850 to 1950 censuses indicate the person's age on the official census day, which was June 1 (1850-1900 and 1930-1950), April 15 (1910), and January 1 (1920), even if the enumerator visited the household on a later date.  Although the person's age is not an exact date of birth, it provides an approximate date that is useful (1) for tracking the person from one census to the next, especially if other people have the same name, and (2) for locating the person in any existing vital records.
  • The 1900 census (column 7) indicates the person's month and year of birth.  
  • The 1870 census (column 13), 1880 census (column 7), and 1950 census (column 11) indicate the month in which the person was born, if born "within the year," that is between June 1, 1869 and May 31, 1870 for the 1870 census, or June 1, 1879 and May 31, 1880, for the 1880 census, or June 1, 1949 and May 31, 1950, for the 1950 census.

Place of birth

  • The 1850 to 1950 censuses indicate the person's state or country of birth, which helps narrow the geographic scope of search for the specific town of birth.

Date of marriage

  • The 1850 census (column 10), 1860 census (column 11), 1870 census (column 14), and 1880 census (column 12) indicate whether the person had married within the year.  "Within the year" means during the year before the official census day, that is, between June 1, 1849 and May 31, 1850, for the 1850 census; between June 1, 1859 and May 31, 1860, for the 1860 census; between June 1, 1869 and May 31, 1870, for the 1870 census; and between June 1, 1879 and May 31, 1880, for the 1880 census. 
  • The 1900 census (column 10) and 1910 census (column 9) indicate the number of years of marriage for each married person.

Number of children

  • The 1900 census (column 11) and 1910 census (column 10) indicate how many children were born to each woman. The 1900 census (column 12) and 1910 census (column 11) indicate how many of those children were still living. These clues can help determine whether the researcher has identified all children in a given family, and whether any were deceased when either census was taken.

Immigration to the United States is the act of moving to this country from a foreign country.

  • The 1900 census (column 16), 1910 census (column 15), 1920 census (column 13), and 1930 census (column 22) each indicate the person's year of immigration to the United States. This information should help in locating an immigration record such as a ship passenger arrival list or a border crossing record for arrivals at the U.S.-Canada or U.S.-Mexico land borders. 

Naturalization is the process by which a foreign-born person becomes a U.S. citizen. 

  • The 1900 census (column 18), the 1910 census (column 16), and 1920 census (column 14), and 1930 census (column 23) indicate the person's naturalization status. The answers are "Al" for alien, "Pa" for "first papers," and "Na" for naturalized.
  • The 1920 census (column 15) indicates the year in which the person was naturalized.
  • The 1950 census (column 14) indicates the person's naturalization status with the answers "Yes" or "No."  Persons who were born abroad of American parents are indicated as "AP."  

Foreign-born parents

  • The 1870 census (columns 11-12) has check marks if the person's parents were "of foreign birth."
  • The 1880 census (columns 25-26), 1900 census (columns 14-15), 1910 census (columns 13-14), 1920 census (columns 21 & 23), and 1930 census (columns 19-20) indicate the person's parents' birthplaces.
  • The 1950 census (column 15) indicates the person's parents' birthplaces only for persons on sample lines.

Military Service ​may resulted in the creation of military service records, a pension file, and possibly other records.

  • Civil War Service in Union or Confederate Army or Navy
    • The 1910 census (column 30) indicates whether the person was a "survivor of the Union or Confederate Army or Navy." The answers are "UA" for Union Army, "UN" for Union Navy, "CA" for Confederate Army, and "CN" for Confederate Navy. These clues may lead to military service and pension records; see Civil War Records and Confederate Pension Records for more information.  A word of caution, however:  Columns 30-32 are often "overwritten" with numbers like 2-1-0-0 or 6-9-0-0. These numbers are not the answers for columns 30-32, but were data summaries used by Census Bureau tabulators in Washington, DC, to compile statistical data.
    • The 1930 census (column 31) indicates Civil War veterans with the abbreviation "CW."
  • Military Service, 1898-1950
    • The 1930 census (column 31) indicates military service in other wars with "Sp" for Spanish-American War, "Phil" for Philippine Insurrection, "Box" for Boxer Rebellion, "Mex" for Mexican Expedition, and "WW" for World War I.
    • The 1950 census indicates military service for males on sample lines, with checkmarks for service in World War II (column 33a), World War I (column 33b), or at any other time, including in 1950 (column 33c).

Real property.  Ownership of real estate resulted in creation of deeds, mortgages, and property tax records held by appropriate county records offices.

  • The 1850 census (column 8), 1860 census (column 8), and 1870 census (column 8) indicate the value of real property (land) owned by each person.
  • The 1900 census (column 25), 1910 census (column 26), 1920 census (column 7), and 1930 census (column 7) indicate whether the person owned ("O") or rented ("R") the home or farm.
  • The 1900 census (column 26), 1910 census (column 27), and 1920 census (column 8) indicate whether home and farm owners owned their property with a mortgage ("M") or free of mortgage ("F").
  • The 1930 census (column 8) and 1940 census (columns 4 and 5) indicate the value of home, if owned, or the monthly rental, if rented.

Economic data

  • The 1850 to 1950 censuses all indicate the person's occupation for persons over the age of 14.  
  • If the answer is "farmer" on the 1850-1880 censuses, the researcher should look for information about the farmer's land ownership, crops, and livestock in the 1850-1880 agricultural census schedules.  See Nonpopulation Census Records for more information.
  • If the person was a saw or grist miller, cheese maker, or other "manufacturer" on the 1820 or 1850-1880 censuses, the researcher should check the 1820 and 1850-1880 manufacturing census schedules.  See Nonpopulation Census Records for more information.
  • For persons over the age of 14 years on sample lines only, the 1950 census indicates the amount of money the person earned from wages and other sources (31a, 31b, and 31c) and the amount the person's household earned from wages and other sources (32a, 32b, 32c).  

Researchers who use these and other clues in census records will be more successful and thorough in their genealogical research.