The Archive material held by La Société falls into three main categories. First, there  are the records of the activities of the Society itself and its Groups: records of wild flowers identified, birds seen, rainfall and sunshine, well water levels, historical projects undertaken (such as a study of the earliest tombstones). 
Second, there are miscellaneous donations of unpublished papers, such as diaries, theses or works of scholarship (including the working papers of A.H.Ewen, co-author of The Fief of Sark 1969, on genealogy of Sark families and the inheritance of tenement lands), together with photographs and newspaper cuttings. From World War II there is an important collection of papers relating to the Friends of Sark, who became pen pals to islanders who were interned on the continent, and later raised money for post-war reparations; and a documentary record ‘Sark and Channel Island Deportations’ by Tom Remfrey. 
Third, since 2009 we have become  custodians of  some 1500 documents comprising the Seigneurie Archive. These are the working papers of Sark’s Seigneurs from Helier De Carteret, granted the island by Elizabeth I in 1565, down to the death of Dame Sibyl Hathaway in 1974. They were calendared and catalogued in 1991. Roughly half the documents are deeds for property transactions in Sark and Guernsey. These include the property holdings of the Sark judge and Guernsey merchant John Le Gros (whose daughter Susanne bought the fief in 1730) and also of the Guernsey privateer John Allaire (whose daughter purchased the fief in 1852). The other half are miscellaneous, mostly relating to the administration of the Seigneurie estate (collection of rentes and tithes) and the government of Sark. There are records relating to milling and mining, the Sark militia, the appointment of Church ministers and the building of Sark church and schools. The period 1927-1974 is represented by typescript drafts of Dame Sibyl’s writings and by copious newspaper clippings of her public appearances to promote Sark in Europe and America.

​