Finding an ancestor's birth date can be frustrating for many genealogy beginners. To find a birth date, you have to understand what records can answer your question. It's not always easy.
Before I answer the question, ask yourself, how deep do you want to research?
Will one record suffice in your quest to find a birth date for your ancestor?
Now many experienced genealogists will scream, "NO!!!! One record is not enough!!!"
But the question I'm asking you is essential, are you a professional, hobbyist, or a casual name seeker?
If you're a casual name seeker, use whatever hints show up on FamilySearch, Ancestry.com, or MyHeritage. And if you're really casual and you're using FamilySearch, you may find the information other researchers have gathered and compiled on the family tree. Don't change anything unless you have actually discovered new information.
If you're a hobbyist, you will want to dig a little deeper into online sources by consulting the FamilySearch Wiki for your particular area's possible record collections. It's the backbone for a quest that's a little more than casual.
If you're seeking professional certification, hoping to do client work, or want to research at that level, it pays to know the likely records that can answer your question. You'll write a research plan and search for all of the documents.
Finding An Ancestor's Birth Date Depends on the Time Period
The first thing you need to know is the time period. The further back in time you search, the fewer records that you have available for your ancestor.
There are categories of records to search based on their reliability (not infallibility). Additionally, some resources are more readily available online than others.
Easily Accessible Genealogy Records
Birth Records (more reliable because it's created close to the time of the event by witnesses to the event)
Marriage Records (moderate reliability, self-reporting of own birthdate)
Death Records (less reliable, informant generally wasn't a witness to the birth)
The vital records are great when they were kept. They're also valuable when they recorded additional information than the barest of facts for the event.
Alternatives to Genealogy Vital Records
If these vital records are unavailable online, were burned, or never existed, you'll have to search for alternative sources to build a case.
Census Records - Most US state and federal censuses are available online. The information's reliability decreased as it's not often complete, and the informant is not always specified. However, the records provide clues about the consistency of birth date, even if you have to calculate it from the age reported.
Grave Markers - BillionGraves and Find A Grave have made searching for headstones a cinch, in most cases. The stones' reliability is suspect because of how far removed the death date can be from the birth date, and errors can creep in. However, the grave markers can add additional evidence to a case without the birth certificate that relies on indirect evidence. And in some cases, it might be the only record of an ancestor's existence.
Genealogy Records That Might Have Your Ancestor's Birth Date
Newspapers - Birth Announcements, Wedding Announcements, and Obituaries are among the news features that may provide a birth date for your ancestor. If the publication is online and searchable, the difficulty in obtaining the information substantially decreases. The reliability of the details depends on the unidentified source providing the information.
School Records - not every state or county kept school records. However, for states that did, such as Oklahoma, these records contain details about the birth dates of children listed. The reliability is significant because the parents often reported the birth dates to the school officials to place their children in the correct school grade. Parents, presumably, were witnesses to the birth dates of their children.
Published Family Histories - Many family histories are published and on shelves in libraries and archives. Others are online!!! The reliability of every authored family history should be scrutinized. Still, these histories can be used as evidence in conjunction with additional records.
County Histories - If your ancestor was a first settler, a prominent individual in an area, or related to them, then their birth date might be included in a county history. Mistakes happen regularly in these books, but the information can again support a collection of additional records.
The Most Challenging Genealogy Records for Birth Dates
Bible records - If you can find them, bible records are awesome. Generally, you'll have to ask the person for whom you are working or your extended family's homes (or your attic) if this resource is available. There are website transcriptions, archives, and repositories that may have bible records. You have to hunt for these resources. You might also fiBibleble records in pension files or lineage applications.
Church Records - Compared to Canada, it's more challenging to determine the religious affiliation of Americans. The Canadians placed that information in many of their census records. So, you'll have to look for clues before you seek out church records. Some clues include newspapers, on gravestones, from the cemetery in which they are buried. Sometimes it's the only church in a 60-mile radius. Urban dwellers with multiple church options became very difficult to search. Church records that are online and searchable may be worth the effort. Otherwise, the quest comes down to how deep are you willing to go?
Family Letters - If your family has an archive containing letters detailing birth dates, you are fortunate. Those letters have questionable reliability but are worth reviewing. Correspondence sometimes provides the only evidence that some individuals existed.
Out-of-the-Box Genealogy Records For Your Ancestor's Birth Date
Military Draft records - the more modern, the better
Military Service records
Application for Veteran Headstones
Widow Pension Files
Passenger documents - the more modern, the better
Naturalization records - the more modern, the better
Evaluate The Genealogy Records You Find
Once you find a genealogy record, you need to evaluate them with care. Check out this video to learn how to do just that.