Cemetery records and cemeteries in general are a very large part of our family history and is a significant pursuit for many genealogists. Sometimes, the information on a headstone is the only information available for certain ancestors.
Full disclosure: this is not an area that encompasses a large percentage of my personal genealogical research, so I would not be considered an expert by any stretch. But I have called on a few colleagues to get me at least somewhat conversant.
What can you find in these records? How about birth, marriage, and death information and clues to military service, religion, and organization memberships. Location of the burial plot, tombstone inscriptions, cemetery maps, sexton registers, and headstone photos are also generally available.
Here are a few good primers on the benefits of searching cemetery records:
I have not performed separate searches from Find a Grave, Billion Graves, or Interment.net by county or individual cemetery as that would be time prohibitive. Those sites are very useful, and you might find references to them from sub-collection links.
Note: Some of the links listed take you to a FamilySearch Collection of digital images. Near the bottom of the page under Film/Digital Notes is the name of each sub-collection. If there is a camera icon at the right of the name (in the Format column) then the collections’ images are browsable. If there is a camera with a key icon, it is only available at a Family History Center or affiliated library. If there is a film reel icon, then it is only available in microfilm format, not digital. To take full advantage, please make sure that you are logged in to FamilySearch. The results may be different if you are signed in, rather than not.
Below, listed by state are links to cemetery, burial, and interment records as well as indexes and tombstone inscriptions that are available for free online.