- The name Treston appears in the Claremorris and Ballyhaunis area of county Mayo from the 18th century. They seem to have been closely associated with the Dillons of Feamore, parish of Bekan, barony of Costello. At the time of Griffith's Valuation, the Trestons held three townlands in the parish of Kilcolman and one townland in the parish of Mayo, barony of Clanmorris, previously part of the estate of Patrick Kirwan of Dalgan. They also held a townland in the parish of Bekan, barony of Costello, county Mayo and a townland in the parish of Kilgefin, barony of Ballintober South, county Roscommon. The representatives of John Treston of Carrownedan advertised 1625 acres for sale in counties Mayo and Roscommon in the Landed Estates' Court in 1865. The county Roscommon lands were in the baronies of Ballintober South and Frenchpark. In 1876 four Treston brothers held almost 1900 acres in county Mayo. At the time of Griffith's Valuation James Treston was one of the principal lessors in the parish of Kiltullagh, barony of Castlereagh. In the 1870s James Treston of Tulrahan, Ballyhaunis owned over 180 acres in county Roscommon. 500 acres of the estate of Michael Francis Treston in the barony of Clanmorris, county Mayo was offered for sale in the Land Judges' Court in July 1890.
- 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.
Bourke (Curraghleagh & Rahasane)
- Isidore Bourke, a younger son of Joseph Bourke of Carrowkeel, county Mayo, had an estate in the parish of Kilcolman, barony of Clanmorris, county Mayo, which he purchased from the Kirwans of Dalgan. He also held lands from the Moores, formerly of Brees, county Mayo and of Cloghan Castle, county Offaly. In 1876 his son, Captain Joseph Cormack Bourke of 29th Foot, held 4141 acres in county Mayo. Captain Bourke died in 1877 and was succeeded by his brother, Walter Bourke of Curraghleagh and Rahasane Park, county Galway, which he must have bought from the Joyces in the mid 1870s. Walter Bourke was murdered outside the gates of Castle Taylor, Ardrahan, county Galway, in 1882. A third brother, Isidore Bourke, sold 4181 acres in county Mayo to the Congested Districts' Board in February 1902 for £30,394.
- A branch of the Bourkes of Moneycrower or Bunacrower, later Earls of Mayo, settled at Oory [also spelt Urey/Urrey], parish of Tagheen, barony of Clanmorris, county Mayo in the 17th century. They intermarried with other Bourke families and with the Fitzgeralds of Turlough, Kellys of Kelly's Grove and Fiddane and with the Shees of Castlebar. Burke's ''Landed Gentry'' records four generations of Bourkes residing at Oory until the estate was sold in the mid 18th century. Later generations of the family settled in Jamaica and England. One descendant, Eliza Jane Dennis of Jamaica, married James Hewitt Massy Dawson in 1800. By the time of the first Ordnance Survey the Brownes of Brownhall were in possession of Oory and the Nettervilles held Coarsefield, which was probably part of Oory under the Bourkes. One branch of the family lived at Curry in the parish of Mayo in the late 18th century and intermarried with the Brownes of the Neale. Two daughters and co-heiresses married Patrick Kirwan of Claremount and Charles McManus of Barley Hill and appear to have shared the townland of Curry - Curry (McManus) and Curry (Kirwan).