The Donnellan estate was in the parish of Taghboy, barony of Athlone, county Roscommon. In the 1830s the estate belonged to McGann Donnellan. By the early 1850s the estate was in the possession of the Reverend Edmond Riley and John Owen who advertised their estate of 1,107 acres for sale in the Encumbered Estates Court. The petitioner was Catherine Edwards Donnellan. By the time of Griffith's Valuation the McGann Donnellan estate was in the possession of the Reverend James McIvor and Percy Magan.
- Encumbered Estates’ Court Rentals (O’Brien), Riley & Owen, 9 July 1852, Vol 17, MRGS 39/008, (microfilm copy in NUIG); National Archives of Ireland