The archive is comprised of letters and papers relating primarily to Katharine Tynan. There are also letters to her husband Henry Hinkson, and a substantial portion of material generated by her daughter Pamela; both Henry and Pamela were also novelists.
The large body of correspondence in the archive emanates both from within the family and from their many friends in both British and Irish literary and political circles. Among these are the Yeats family (including 2 letters from W.B. Yeats and 2 letters from J.B. Yeats), George William Russell ('A.E.'), Alice and Wilfrid Meynell, Lord and Lady Aberdeen, Jane Barlow and May Sinclair. Also included are individual or small groupings of letters from such significant and diverse figures as Lawrence Binyon, Edmund Blunden, Richard Church, John Galsworthy, Eva Gore-Booth, Augusta Gregory, Rudyard Kipling, Francis Ledwidge, Walter de la Mare, Edith Nesbit, Siegfried Sassoon, George Bernard Shaw, Edith Somerville, H.G. Wells and Charlotte Yonge.
Most of the correspondence in the collection relates to Katharine Tynan, with a smaller number of letters to her daughter and husband, plus some inter-family letters. There are also some letters between unrelated third parties; many of these relate to the First World War (Tynan was known as a war poet and kept up a correspondence with people who contacted her because of her poetry). There are around five thousand letters in total.
There are also a number of transcripts of letters, some of which are copies of letters sent between third parties, and some of which are copies of originals that were sold by the family: W.B.Yeats's letters to Tynan were sold to the University of Austin, Texas, and some other literary letters were sold to Southern Illinois University, Carbondale. Pamela Hinkson made transcripts of some (but not all) of the letters dispersed in this way. Most of these transcriptions are currently closed to readers for copyright reasons.
The archive also includes a copy of Katharine Tynan's diary, consisting of two volumes covering the period from July 1914 to September 1915, when she abandoned it. This contains many inserted letters received by Tynan which give accounts of the War and its effects. The diary was intended to be published (as A woman's notes in war-time), but this did not ultimately occur. The edited and typed version of the diary is held by University College Dublin.
In addition, the archive includes Tynan's first poetry notebook (containing her earliest completed poem, dated 1878), although this item is badly damaged and incomplete.