The Thomond deeds are Irish deeds relating to lands and property in Thomond, County Clare, preserved in the Library of Trinity College, Dublin. The collection, written in Irish and mainly consisting of "deeds and instruments related to property", has undated documents from the 12th through the 14th centuries; for the most part, however, the documents are dated, between 1419 and 1619. It provides an important background for later legal writing in Ireland.
Hardiman, 1826, says of these deeds
The abolition of the ancient tenures of Ireland, ... during the sixteenth and seventeenth centuries, rendered deeds and writings in the Irish language, ... in a great degree useless. Other combining circumstances, but chiefly the policy and care of successive English grantees to destroy all evidence of previous rights and possession of the natives, caused those domestic documents to become so scarce, that the few which escaped the general wreck are, at the present day, esteemed valuable rarities, ...
Russell, Charles William (1869-05-24). "On an Agreement, in Irish, between Gerald, Ninth Earl of Kildare, and the MacRannalls". "Proceedings of the Royal Irish Academy". 1 X. Dublin: M.H. Gill. pp. 482–483.