Deeds, correspondence, pleadings and papers in legal actions, 18 cent.-20 cent., relating to estates in Anglesey, Caernarfonshire and Merionethshire. Miscellaneous papers include Caernarfon borough court rolls, 1392-1393, 1695-1697, and a rental, 1691-1692; papers relating to Benefit Building Societies in Caernarfonshire, 1861-1890; and a minute book of Porthaethwy ferry, 1782-8.

Original manuscript of the Welsh text of Saunders Lewis's address to the jury during his trial at Caernarfon Assizes, October 1936, for arson at the Penyberth Bombing School. The Welsh text, described by Saunders Lewis as 'partly strict translation but in part a separate and different composition' (see NLW MS 22951C, f. i), was subsequently published as a pamphlet Paham y Llosgasom yr Ysgol Fomio (1936).

Abstracts of some cases of Caernarvonshire interest heard in the Court of Star Chamber, temp. Elizabeth.