Llythyrau, 1915-1936, yn bennaf at ei deulu tra bu'n gwasanaethu yn y fyddin, 1915-1919; teipysgrifau a llawysgrifau o'i ddramâu a sgriptiau radio, 1920-1936, a thorion papur newydd o adolygiadau, 1926-1940; barddoniaeth, caneuon, parodïau, rhyddiaith a deunydd arall, 1924-1932; copi teipysgrif o 'Ann y Wernolau',drama gan ei fam, Mrs Teifi Jones, 1921; a deunydd amrywiol a ychwanegwyd gan D. Gwenallt Jones tra bu'n ymchwilio ar gyfer Cofiant Idwal Jones, 1934-1957. = Letters, 1915-1936, mainly to his family whilst serving in the army, 1915-1919; typescripts and manuscripts of plays and radio scripts, 1920-1936, and newspaper cuttings of reviews, 1926-1940; poetry, songs, parodies, prose and other material, 1924-1932; a typescript copy of 'Ann y Wernolau', a play by his mother, Mrs Teifi Jones, 1921; and miscellaneous material added by D. Gwenallt Jones while researching Cofiant Idwal Jones, 1934-1957.
Derbyniwyd bocs ychwanegol o bapurau gan Mrs Eirain Rees (nee Jones), Medi 2008. Mae'r grŵp yn parhau heb ei gatalogio.