- Port became part of the Peyton estate through the marriage of John Hamilton Peyton to Mary Cunningham, heiress of Port, in 1814. John Hamilton Peyton of Port was High Sheriff of Leitrim and in 1851 was a member of the Grand Jury for Leitrim. In the mid 1850s the house at Port was occupied by George Latimer. The Port estate, 726 acres, was advertised for sale in the Encumbered Estates' Court on 28 June 1853. Included in the sale was the townland of Ballyglass South, 555 acres in the parish of Kilcroan, barony of Ballymoe, county Galway. This townland was in the possession of Patrick O'Connor, who had purchased it at the Encumbered Estates Court sale, at the time of Griffith's Valuation. The Freeman's Journal gives details of the purchasers of the county Leitrim property. In January 1865, property in county Leitrim owned by Anna Cunningham was sold in the Landed Estates Court. Charles W. Peyton was the petitioner to the sale and one lot was purchased in trust for him while the second lot was purchased on behalf of the Earl of Leitrim.
- A branch of the O'Conor Don family who resided at Dundermot for 2 generations in the 19th century. In 1683 Hugh O'Connor was granted over 1,800 acres in county Roscommon, including the castle of Ballyntobber and lands at Laraha and Ross. At the time of Griffith's Valuation, Patrick O'Conor held land in the parishes of Kilcroan and Kilbegnet, barony of Ballymoe, county Galway, and in the parishes of Oran and Drumatemple, barony of Ballymoe, Lissonuffy, barony of Roscommon, county Roscommon. Some of this land was held from the Blakeneys and some of the land in the parish of Oran was offered for sale by the Brownes of Castlemagarrett, county Mayo in May 1852. His brother Roderic also held land in the parishes of Oran and Drumatemple. In 1851 some of Roderick O'Connor's land in the parish of Drumatemple was advertised for sale in the Encumbered Estates' Court by his assignee Christopher Hume Lawder. From 1853 Patrick O'Conor held Laragh and Ross, which adjoined the demesne of Dundermot, from Arthur Irwin Mahon. Mahon advertised these lands for sale in May 1856. Patrick O'Connor and Charles O'Connor also held extensive lands at Rathconor and Tonlegee, parish of Kilbride, barony of Ballintober South at the time of Griffith's Valuation, previously part of the Croghan estate. In the 1870s Hussey records that the late Patrick Hugh O'Conor of Dundermot owned 2,435 acres in county Roscommon and his brother Nicholas O'Conor owned 810 acres. Nicholas O'Conor, a prominent British diplomat, sold Dundermot. The estate of his daughter Fearga O'Conor was vested in the Congested Districts' Board in March 1915.