An individual's religion can usually be found in a variety of documents. An obituary, wedding announcement, or birth announcement may mention an individual's religion. To get a copy of an obituary, wedding announcement, or birth announcement, a researcher must at least know the approximate date of the event, the full name of the groom and/or the maiden name of the bride for wedding announcements, the names of the new parents or the name of the child for a birth announcement, or the full name of the deceased for an obituary, and the state and city or town where the event took place.
To find the family religion on a death certificate, a researcher must at least know the individual's full name at time of death, the approximate year of the death, and the state or county of the death, depending on when the death took place.
Both family histories and biographies may mention an individual's religion. Besides obtaining them from a particular individual or family, researchers may find copies in local libraries.
Another place a researcher can look is on an individual's gravestone. Many churches have their own cemeteries and in some instances, members of a particular religion or sect may be buried in a cemetery or mausoleum shared by churches of that sect in a particular area.
When all else fails, researchers should be sure to check photo albums, scrapbooks, and diaries owned by members of the family. Unlike today, people in the past used to keep track of special events–like communions, confirmations, baptisms, bar mitzphas, etc.–in scrapbooks or photo albums. Often the entries are dated, but don't have years. For example, Wednesday, August 16. This is especially true with diaries, letters, and clippings found in scrapbooks. Researchers can easily figure out what the year is by using a perpetual calendar or the calendar in a computer program like Microsoft Outlook.
Other items which may offer clues to an individual's religion are certificates, autograph books, cookbooks (with recipes marked for religious holidays), membership jewelry (such as masonic pins), letters, old photographs, school papers (especially Sunday School papers), sewing samplers, and yearbooks.
In addition, individuals often kept religious mementos such as rosaries, religious jewelry, or other religious items, and souvenirs of trips to religious sites. If there's a family Bible, a researcher should look for the version: A Douai Bible would indicate a Catholic family, for example, and a King James Bible could indicate a Protestant family. A copy of the Old Testament or a Torah would indicate a Jewish family.
Finally, a local history about the hometown may indicate what was the predominant religion in the area.