Genealogy: 1840 Census birth year reference chart

census birth yearBy Barry J. Ewell
As you track your ancestor through the U.S. Federal Population Censuses, you can use age to help you

  • Identify individual members of the family
  • Provide clues to confirm I have the right person/family unit as you search each census
  • Provide clues as to relationship in the family
  • Provide clues if I have the right female when surnames change through marriage
  • Provide clues when people use nicknames and other name variations from one census to the next

I have prepared a birth year reference chart for each census to help you identify an estimated birth year for each ancestor.  This article will focus on the 1840 U.S. Federal Population Census.

Learn more about information about age found in the census:

1840 U.S. Census birth year reference chart
In the 1840 US Population Census, learn the approximate corresponding birth years associated with the age groupings provided.   The 1840 census allowed 18 months to be completed.  The first family would have been recorded in June 1, 1840 and the last family in December 1, 1841. The numbers shown in the categories did not distinguish between who was family and any others who were in the household such as relatives, friends, employees, visitors, boarders, servants.

Note: No matter when the census taker came, he was to record who was in the house as of June 1, 1840.  If a child was born after this date they were not to be counted.  If a person died before this date, they were not to be counted.  It is very probable the census taker just recorded who was there the day they arrived.

Age calculated as of June 1, 1840 and does not allow for the 18 month variance.

Age CategoryBorn Between Years
Under 5 years (0-4)1836-1839
5 & under 10 (5-9)1835-1829
10 & under 15 (10-14)1830-1826
15 & under 20 (15-19)1825-1821
20 & under 30 (20-29)1820-1811
30 & under 40 (30-39)1810-1801
40 & under 50 (40-49)1800-1791
50 & under 60 (50-59)1790-1781
60 & under 70 (60-69)1780-1871
70 & under 80 (70-79)1770-1761
80 & under 90 (80-89)1760-1751
90 & over 100 (90 to 99)1750-1759
100 & over (100+)1740 and before