Why does the IGI not contain many of my pre 1840's ancestors?

Question:If they are not on there will they not be on any parish records?
Or does the IGI not contain all the parish records?

Best Answer - Chosen by Asker: If they are not on there will they not be on any parish records?
Or does the IGI not contain all the parish records?

The information on IGI isn't always complete or correct. The marriage entry for my Great Grandparents shows the wrong Parish Church and the wrong year. I have verified the Church entry, and hold a marriage certificate. Anyone know if there is any way to correct IGI?
Church of England registers usually start in the 1600s, but vicars weren't always helpful in their early record keeping. You see "John Smith was married", "John Smith married his wife", or "John Smith and Mary".
There are still a lot of Church records not entered on the IGI index. Try Googling the parish involved. I found some kind souls have transcribed some of the Somerset BMDs, and they are online. Some Churches have plans and grave locations of their Churchyards, but you would have to visit the Church to find this.

they did not start keeping the records untill 1837, but if you can get to parish records you may find what you are after

It may be that this branch of your Family wasnt particularly religious and therefore didnt have their children christened,keep in mind the large families they would have been having in those days and the cost im sure in having them christened.
Ive also heard of Parish Records being destroyed in fires or by Parish Clerks.I suppose that nearly 200 years on they wouldnt have seen the importance of these documents.

One of the problems is that the IGI has been compiled by The Church of Latter Day Saints members. They were volunteers who needed access to Parish Registers to be able to copy the entries. This means that in some Parishes, due to human error, some entries have been missed and some have been transcribed incorrectly.
Also, to have access to the Registers, the Mormons needed permission from the local Bishop. In some cases, he was suspicious of their motives and access was denied (see Bristol, for example). The reason for the denial was that it was feared the Mormon Church would rebaptise people on the original records so make them members of their Church.
Remember, also, that not all Parish Registers have survived.
Try asking the local Record Office Archivists which Parish Registers have been deposited and if it is possible to have access. I've checked original Registers where they are still in the possession of the Church.

The IGI does not contain all the parish records, they do have a pretty good coverage, I assume by IGI you mean the web site www.familysearch.org, Your ancestors could have been nonconformists, if so try the link below.

Good luck and good hunting