A collection consisting of :
- Letters addressed to Rev. Richard Ellis, Vicar of Tremeirchion from various correspondents including Hester Lynch Piozzi. Their contents mainly relate to domestic matters, payments of tithes and poor rates, the management of family property in the township of Hendregyda and the curacy of Tremeirchion. Also, letters from Rev. Christmas Evans to John Jones, printer of Trefriw; from H.W. Williams (1773-1849) in Edinburgh to a London publisher; from Dean Cotton of Bangor to Elizabeth Bridge.
- The letters addressed to W.O. Roberts are written by such correspondents as Alltud Eifion, Carneddog, O. Gaianydd Williams and Bob Owen, Croesor.
- A visitors book of Tan-y-Bwlch Cottage in Capel Curig, 1847-1869, now known as the Cobden's Hotel.
- A file of letters relating to the 1879 Royal National Eisteddfod held in Conwy.
- Bundles of bills and receipts, for the most part from towns and villages in the Conwy Valley, which throw light upon the nature and prices of the commodities supplied. Included are brewer's licences etc. relating to the Royal Oak, Caerhun.
- Notes by W. O. Roberts on the history of the Conwy Valley and the Llandudno Waterworks.
- A bibliography relating to Caerhun and Llanbedrycennin containing not only names of books and pamphlets, but also of ancient monuments.
- Deeds and documents relating to properties in the Conwy Valley, in particular Berth Lwyd in Caerhun. Also, Quarter Sessions documentation such as warrants and orders.
- Part of the manuscript of William Williams of Llandegai, relating to the topography of Llandegai and surrounding area.