The three vital records that you will need to obtain from an ancestor are: birth, marriage and death. It is best to begin with the last thing your ancestor did, which was to die. From there, you work back in time. Not many death or birth certificates exist before 1850. For those, you would need to obtain 2 sources (such as a census and a death certificate that agree to prove a person's birth.)
1. Death records
You will need to write to the state's Department of Health or Vital Statistics to obtain the death certificate (DC). Each state charges its own fee. Your local library may have a booklet called, "Where to Write for Vital Records." The Mormon (LDS) church has this booklet, too. Also the addresses may be obtained from the Handybook or online at: http://www.cdc.gov/nchs/howto/w2w/w2welcom.htm. ***NOTE***A death certificate is a primary source for death only. Any other information you get off the death certificate (like your ancestor's birthday) is a secondary source. And remember, the DC is only as accurate as the person (informant) who provides it (It is possible that the informant is the spouse of the deceased, who may be very upset by the death of the loved one). If you are hunting down your ancestor's parents and the DC doesn't provide it, you may want to try a sibling's DC.
a. Death Indices
Many states have made an alphabetical index of their death registers. Some states have both the index and record on film. If your ancestor died and you don't know exactly when, you will find this a useful aid. These were filmed and are available from your FHC. You may also want to check with a state archive to see if a death index is in existence if your state is not listed below. An online source of death indices can be found at: www.deathindexes.com. Some information that may be found on a death index: deceased's name, county died in, Social Security number, spouse's first name (if survived by a spouse), the state number and the registration number and possibly the date of birth. (* means the death certificate was filmed too).
CA 1905-1993 NJ* 1848-1900
DE* 1855-1888 (certificates up to 1910) NC* 1906-1950
FL 1877-1969 OH 1908-1936
HI 1909-1949 OR 1903-1994
ID* 1911-1937 SD 1880-1990
IL 1916-1942 TN* 1914-1925
KY 1911-1986 TX 1903-1994
ME 1892-1922 VT 1871-1908
MA 1841-1971 WA* 1907-1979 (certificates up to 1952)
NH Pre-1900 WI* 1862-1907
Reference: Lehmann, Joy. Are you Using Death Indexes in Your Research? Heritage Quest, (magazine), Issue #67, Jan/Feb 1997, page 15.
While you are waiting for that death certificate to arrive in the mail, you may wish to check for an obituary on your ancestor. You can find obituaries in your local public library. Your library may have "Newspapers in Microform" and/or "Union List of Newspapers". The Gale Directory of Publications has more current newspapers. Most states also have a bibliography of newspapers. Three things to keep in mind while reading obituaries: Who said it? When did they say it? and How did they know? The obituary may give you a birth town, the island or maybe just "Azores," "Madeira," or "Portugal." It will list the surviving spouse (if any) as well as surviving offspring. It may list places of where the deceased lived, and may even give you a time line. It may include the ancestor's occupation and how long in that occupation. Sometimes, you will find an article in the newspaper about the deceased, especially if your ancestor was prominent, or possibly died in a tragedy. A side note on newspapers here: some older newspapers have "Society" sections where they may say the Mr. & Mrs. ____ went to visit their daughter in ____.
2. Marriage records
When looking for your ancestors' marriage (if they married in America), the record or register will prove the marriage took place. The license or application gives lot of genealogical information, so this is quite good to obtain. Also, getting a photocopy from the church marriage books could give the town, particularly if they married in a Portuguese community. The witnesses to the marriage could be relatives. The parents of the bride and groom could be listed. Some things you may run across when looking for the marriage are the bond (money put up by the groom) or a consent affidavit (parents saying OK to the marriage). Most marriages can be easily found from 1600 on at the place where it occurred. In New England you may find them at the town level; most other states you find them at the county level. To approximate a year for marriage, subtract 2 years from the birth of the oldest child.
3. Birth records
Birth records didn't really begin until about the turn of the century (1900). A person who needed a certificate and didn't have one filed the information on a form themselves (this began around 1937). This is called a Delayed Certificate of Birth. For the birth of ancestors before the records were kept, you would need to use the U. S. Census, family Bible, or baptismal records. But if you are dealing with your immigrant, he may not have an American birth certificate. You may want to get the birth certificates of the ancestor's offspring. It may offer you other clues.