- This Irwin estate was principally situated in County Roscommon but some property was also held in the Barony of Coolavin, County Sligo.
Irwin (Roscommon & Galway)
- Andrew Irwin, of Ballymore, Boyle, county Roscommon, held over 700 acres in county Galway in the 1870s. The representatives of John Irwin, a minor, were lessors of property in the parish of Eastersnow, barony of Boyle, at the time of Griffith's Valuation. Earlier, in March 1852, the estate of Thomas Irwin, the elder, at Granny East, barony of Boyle, was offered for sale in the Encumbered Estates court. This included a "comfortable residence" depicted in the sale notice.