As noted in Part I on the caveats when looking at a census, the main problem researchers make is to presume something when looking at the data in front of them. So, you found your ancestor listed on a census, and that means he or she was alive on the enumeration date. Maybe, maybe not!
It is important to remember that just because a person's name is on the census, it does not mean the person was alive on the date of the enumeration.
The enumerator was instructed to list the names of all family members as it was composed "on the official date of the census." This is not the date of the visit by the enumerator. If you are trying to calculate the last date an ancestor was known to be alive, you will need to use the official census date for that census year.
Official census dates:
- 1790-1820 First Monday in August
- 1830-1880 June 1
- 1890 First Monday in June
- 1900 June 1
- 1910 April 15
- 1920 January
- 1930 April 1
As an example, the first Monday in June, 1890, was on 2 June. Now many people may not be lucky enough to have their ancestor as one of the 6,160 names available on a card index for that census year. Most of that census was destroyed in a fire in 1921. If you need to calculate the dates for 1790 through 1820, I recommend the following website. Just enter the year you are looking up and then click on the month of August:
This calculator will also help you discover the day of the week ancestors were married, born, or died and adds detail to your family history records.
A great number of microfilm census records are indexed by head of household, and that leads us to another presumption or assumption that people often make when doing research. Sometimes one assumes that if an ancestor is not listed in the index, they must have died sometime between the last census taken and the next one. This is not necessarily true. Many times the person you are looking for is living with a son or daughter, so you won't find them in the index. This means you need to track down the children of that ancestor before jumping to the wrong conclusion. This emphasizes the need to find marriages for the siblings of your ancestor as well as your own direct line. Unless you know the surname of a married daughter, you may miss her father and/or mother entirely.
I recommend always tracing the collateral lines when possible. I have tracked lines through four census years (40 years) and found a brother of a widow living in her household. That lead to an all-important surname that was unknown until then.
Using the census records and collateral lines, you will also accumulate areas of the country where family members lived, and it will provide clues to possible areas to search for marriage, birth, death and cemetery records. Happy tree climbing!