My last few posts have dealt with life expectancy. As I mentioned, there are numerous causes for the termination of life. When a family consistently reaches into the 70s or 80s, but one family member suddenly passes in his/her 50s, look for the cause.
Death certificates are the ideal source for cause of death. The catch here is that many states or other jurisdictions were not required to keep death records until the 1880s into the early 1900s,
Obituaries are another excellent source. Small town papers generally offer more details in their obits than do larger metropolitan "rags." Unfortunately, many papers only print death notices. Name, date of death and funeral info may be all you get.
Cemetery records might provide cause of death with the burial permit or record. Some cemeteries keep "day books," or other detailed records. Request them, if available!
Diaries and journals are also a possible source. A family member may have kept a personal record. Neighbors or local citizens may have kept journals as well. Some of these chronicled the day to day life of the neighborhood, town, village or city. This would include birth, marriage and death references of people known to the diarist. Many libraries have journals on microfilm or in the manuscript division.
Military records and pension files can be a source for servicemen and women. They may also include deaths of other family members.
Last, but not least, family members may be able to provide the details you need.