The IGI contains information submitted for vicarious ordinances by LDS researchers, records obtained from contributors who are not members of the church, and data taken from various birth or marriage records that Church members have microfilmed. The index contains hundreds of millions of records of individuals who lived between 1500 and 1900, primarily in the United States, Canada, and Europe.
The IGI contains many duplicate names, accumulated over time from many sources, so all data retrieved from the index should be checked carefully, and compared with similar entries. Cross-checking is facilitated by the fact that every record contains information on who submitted it and when. The IGI can be searched online at FamilySearch, the LDS genealogy website.