Cemetery Burial Indexes on the Internet – General
The Online Death Records Indexes, Cemeteries and Obituaries website has listings for some individual cemeteries with burial indexes. They are listed by state, then by county.
That website’s General Cemeteries Page has listings for websites that have collections of cemetery burials for more than one state, including the Tombstone Transcription Project, Find-A-Grave and others.
Military Cemeteries
The U.S. Department of Veterans Affairs Nationwide Gravesite Locator is a database of burials in national military cemeteries throughout the United States.
The Online Military Indexes and Records website lists some Civil War cemeteries that have online databases.

Jewish Cemeteries
The JewishGen website has a Worldwide Registry for Jewish Burials.
The New York City section of the Online Death Indexes website has listings for six Jewish cemeteries in Queens: Online New York City Death Indexes and Cemetery Burials.
Some individual Jewish cemeteries can be found listed throughout the Online Death Indexes website. See the first link above.
Catholic Cemeteries
The Online Death Indexes Directory has listings for online Catholic cemetery burials in Fresno and Orange County, California; Wilmington, Delaware; Palm Beach, Florida; Portland, Maine; St. Louis, Missouri; Omaha, Nebraska; Newark, New Jersey; Cincinnati and Dayton, Ohio; Eugene and Portland, Oregon; Providence, Rhode Island; Seattle, Washington; Milwaukee, Wisconsin; and other places. Some of these databases cover the entire Diocese or Archdiocese. See: Catholic Cemeteries with Online Burial Indexes in the USA
Top Photo: Fort Logan National Cemetery, Denver, Colorado
Bottom Photo: Emanuel Cemetery at Fairmount, Denver, Colorado