- This junior branch of the Kirwans of Cregg Castle, county Galway, were merchants in the city of Galway, who received grants of lands, over 3,000 acres, in the parishes of Kilcolman and Mayo Abbey, barony of Clanmorris, county Mayo, under the Acts of Settlement. They bought the Dalgan estate from the Earl of Clanricarde in 1771 and so acquired lands in the parishes of Kilmainemore, Moorgagagh and Shrule, barony of Kilmaine, and in the parish of Toomore, barony of Gallen. At the beginning of the 19th century they moved their main family residence from Claremount on the outskirts of Claremorris to Dalgan near the village of Shrule. In 1853 the entire estate of Patrick Kirwan was sold in the Encumbered Estates' Court for £48,300. The purchaser was the Duke of Bedford on behalf or in trust for Lady de Clifford. The Kirwan family moved to Gelston Castle in Scotland.
- In 1853 the Dalgan estate was bought by the Duke of Bedford for Lady de Clifford, who was the wife of his first cousin. The estate was comprised of lands in the baronies of Kilmaine, Clanmorris and Gallen, county Mayo and in the barony of Clare, county Galway. Her estate was mainly located in the county Mayo parishes of Mayo, barony of Clanmorris, Kilmainemore, barony of Kilmaine and in the parish of Donaghpatrick, barony of Clare, county Galway. In 1876 Lord de Clifford owned 11,594 acres in county Mayo and 1406 in county Galway. Most of the county Mayo estate was vested in the Congested Districts' Board in February 1914 and an offer had been accepted for the county Galway acreage by March 1916.
In 1802 McParlan recorded that Lady de Clifford held a large estate in county Leitrim but was not a resident proprietor. Her grandmother was Sophia Campbell of the Mount Campbell, county Leitrim, family.