- 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 Category||Born 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|