The volumes contain hand-written records of births, marriages and deaths and in some cases span decades from a single church.
They have been ‘on deposit’ with the library for about 20 years, said chief librarian Sue Laker.
A digitisation project carried out in partnership with online genealogy and family history service Findmypast has since taken place, with the support of the Church and helped by volunteers from La Societe’s Family History section, who spent many hours indexing the volumes to make them searchable.
But because of data protection laws, there are cut-off dates for what can be accessed, with the most recent births and baptisms available being no later than 1926.
The cut-off date for accessible marriage records is 84 years ago while that for burials and deaths is 25 years.
Ms Laker said that Guernsey was fortunate to have such a wealth of these records, since in England similar records from churches have not survived.
The oldest volume in the collection is from the Town Church and dates back to 1563, a time when the records were all written in French and when penmanship was not always at its best.
With the registers now in the climate-controlled strongroom of the Island Archives, States archivist Vikki Hart said the work has started to catalogue them.
‘These records from all the parish churches are so important in the history of our island and for social history and family history research,’ she said.
‘What makes them all the more important is that the Civil Register was only introduced in 1840. Before that date if a resident was born, married or died, the church records were the only real records of family life and history.’
The archives include records from St Barnabas’ Church, where the Island Archives have been for about 20 years.
‘We’re really pleased to bring those back “home”,’ she said.
Mrs Hart acknowledged the support for the project of former Dean of Guernsey, the Very Rev. Tim Barker, who was one of the partners involved in getting the records digitised.
His successor, the Ven. Matthew Trick, said that the transfer of Church records to the Island Archives was a significant step in preserving an important part of the island’s shared history.
‘These records tell the story of generations of islanders through baptisms, marriages and burials, and are of immense value not only to the Church but also to families, local historians and genealogists,’ he said.
‘I am grateful to all who have contributed to the digitisation and transfer project, particularly my predecessor, whose vision and commitment helped bring this work to fruition.
‘The registers have long been cared for by the Priaulx Library, and it is good to see them now housed within the Island Archives, where they will remain accessible to the public and safeguarded for future generations.
‘As Dean of Guernsey, I am delighted that these records will continue to help people discover more about their family history and deepen their understanding of the rich heritage of our islands.’