The Powys-Lybbe family held extensive estates in Oxfordshire, principally in the south of the county, in such places as Whitchurch and Goring. In addition they also held property in other counties, particularly Berkshire. There are also deeds relating to their interest in properties in the midlands and the south of England. The collection mainly consists of title deeds, but in addition there are loose papers at the end of the collection relating to enclosures and tithes of various places and finally there are probate items which mainly consist of wills of various members of the Powys-Lybbe family. The collection as a whole dates from the 14th-20th centuries.
The material has been deposited with Oxfordshire Record Office at various stages in the last sixty years; the first depoit being in 1935, which was assigned the accession number 8. There were further deposits in 1983 (accession 2122), 1991 (accession 3301) and 1999 (accession 4472). Accession 8 was originally catalogued under the collection reference PL and a concordance of old and new reference numbers is provided at the back of the hard copy catalogue.