Draft of an Irish dictionary by Matthias O'Conway, of Philadelphia (formerly of Galway city), with references to many other languages, several thousand sheets in 10 boxes, 1814-1842.

Míreanna comhchosúla

• Draft of an Irish language dictionary by Matthias O'Conway, of Philadelphia (formerly of Galway), showing meanings of words in Greek, Latin and in modern European languages, c. 1814-1842.
• Correspondence and miscellaneous papers of the family of O'Conway in the United States of America including letters to and by Matthias O'Conway, Gaelic lexicographer of Philadelphia, (formerly of Galway City), early 19th c.
• Notes of the meaning of words by Matthias O'Conway, of Philadelphia, (formerly of Galway), including many Spanish words, also a few Irish words, c. 1814-1842.
• Miscellaneous papers of Matthias O'Conway, of Philadelphia (formerly of Galway City,) including some material for an Irish dictionary, notes on Spanish, printing etc., early 19th c.
• On O'Conway's Ms. Irish dictionary (a quotation from Irisleabhar na Gaedhilge with a note by S. Ó C.):
  de réir: Lyona, J. J.
  Foilsithe / Cruthaithe: (1929)