The material held at the Department of Archives and Manuscripts   is unique and cannot be replaced.  It is a recognised repository and contains over 500,000 manuscripts and records.  The records range in date from the thirteenth to the twentieth centuries and relate in the main to the history of North Wales, its topography and people.

The holdings can be divided into several groups:

1. College Records - e.g. student registers, photographs, minutes of senate, court and council meetings, plans of buildings, records of clubs and societies etc.
2. Maps and Plans - Estate maps and plans will mostly only show features which were of interest to the landowner or the surveyor and will ignore the neighbouring lands.  The most valuable maps are those accompanied by books of reference, which will provide details regarding acreage, land use, occupation etc.
3. Industrial Records - Landed estates commonly exploited minerals and timber resources.  Some of these businesses were run by the estate and some were leased out for rent or royalties, in particular, mining and quarrying enterprises.  Accounts, leases, plans of sections of mines, correspondence are common types of industrial records.
4. Manorial and Tithe Records
5. Personal / Family Papers - e.g. wills, marriage settlements, correspondence, diaries.
6. Miscellaneous - Usually the most interesting section of an estate collection.  May contain literary material or evidence of educational, political or military interests etc

• Baron Hill
• Bodorgan
• Caera
• Dinam
• Henblas
• Henllys
• Lligwy
• Llysdulas
• Parciau
• Penrhos
• Plas Coch
• Plas Gwyn
• Plas Newydd
• Presaddfed

• Beaumaris and Anglesey - administrative records of the borough of Beaumaris
• Anglesey Hunt
• Anglesey Hunting Club
• Sale catalogues
• Melville Richards Place Name Archive