McParlan includes Mr. O'Brien, Drumrahan, on a list of "resident gentleman of property" in 1802. In 1863 John O'Brien offered for sale in the Landed Estates Court over 300 acres in the townland of Drumgrania, parish of Cloone. The particulars indicate that the original lease was from the Tenison estate to Robert Whitelaw. It had been renewed in 1839 from the Tenison estate to O'Brien, Crofton and Norris. Cornelius O'Brien owned several townlands in the parish of Mohill, county Leitrim in the 1850s. In 1864 he offered for sale in the Landed Estates court the rental of lands at Upper and Lower Leitrim, barony of Mohill though the sale was adjourned in June of that year. Lands at Drumrahan were offered for sale by John O'Brien in January and July 1872. He is recorded as owning 250 acres in 1876. William O'Brien advertised over 50 acres for sale in 1851 but they were purchased on his behalf by William Crozier at the sale in the Encumbered Estates Court. He offered over 400 acres in the baronyof Carrigallen for sale in February 1873 but purchased them himself for £4000. William O'Brien is recorded as the lessor of several townlands in the parish of Cloone, barony of Mohill. He was also leasing property at Cloghlough, parish of Carrigallen, from the King estate. This may be the same William O'Brien who was the owner of over 600 acres in Leitrim and whose address is given as Riversdale in 1876. The latter house had previously been occupied by the Shanley family. Jane O'Brien, resident at Waterloo Rd in Dublin in 1876, owned over 500 acres in county Leitrim. Over 500 acres of the estate of John O'Brien were offered for sale by Ellen Ireland in the Land Judges' Court in March 1878, being the interest of William O'Brien, husband of Ellen Ireland.