This article discusses all known manuscripts written by Tadhg Úa Ríghbhardáin, a prolific scribe and illuminator from the North-East Munster and Leinster border area who flourished during the mid-1470s. The history of these manuscripts is updated from the library catalogues where possible, and a new manuscript is added to those we can now list as being in the hand of this scribe — Rennes, Bibliothèque de Rennes Métropole MS 598. A list of all the texts copied by this scribe is provided and various sections of a number of them are reproduced in a discussion of his copying practices. This is followed by an analysis of the scribal and ortho- graphical features typical of this scribe and the article concludes with a discussion of a number of spellings that may reveal aspects of the regional variety of Early Modern Irish that he spoke.