- The Dillons, originally from county Westmeath, were lease holders in the parish of Drum, barony of Athlone, county Roscommon, from the 1720s. In the mid 18th century James Dillon married a daughter of Thomas Hussey and Jane Moore and leased land from his father-in-law. Lieutenant Colonel John Dillon built Johnstown House in the early 1780s and was succeeded by his son, another John Dillon. In the mid 19th century the Dillon estate was comprised of two townlands in the parish of Drum, barony of Athlone, and lands at Kilbegley and Ardnaglug, barony of Moycarn, county Roscommon. In the 1830s and 1840s much of John Dillon's estate was leased to his brother-in-law, Denis Bernard Kelly, who had married his sister Susan. In June 1853 the Dillon estate amounting to 5,419 acres was advertised for sale in the Encumbered Estates' Court. Parts of the estate were sold. The Freeman's Journal reported in June 1855 that over 250 acres in the barony of Athlone ahd been purchased in trust by Mr. Perrin. John Dillon still owned 1,083 acres in county Roscommon in the early 1870s. Soon after his death in 1871 his estate was purchased by James Kelly.
Pim (Co Roscommon)
- In the 1850s Thomas Pim junior held land in the parishes of Cam and Kiltoom, barony of Athlone, county Roscommon, some of which he purchased from the sale of the Dillon of Johnstown estate in June 1853. He was a Quaker and lived in Killiney, county Dublin in the 1880s. In the 1870s he is recorded as owning 499 acres in county Roscommon. 535 acres in county Roscommon belonging to Pim Minors were vested in the Congested Districts' Board on 28 Mar 1912.
- The Wilsons held an estate of just under 300 acres at Carrownolan, parish of Kiltoom, barony of Athlone, county Roscommon in the mid 19th century. Carrownolan was part of the Dillon of Johnstown estate offered for sale in June 1853. In the 1870s the Wilsons still owned their estate in county Roscommon.
- James Kelly was a civil engineer, who worked on the construction of the Ganges Canal in India. In 1863 he married Catherine Jane Fletcher of Birmingham and following the death of her father in 1867 they inherited a sum of money and purchased the Dillon's Johnstown estate consisting of 2,238 acres. In the 1870s James Kelly owned 2,233 acres in county Roscommon. They had a large family and one of their sons continued to reside at Johnstown until the late 1920s. In the late 1930s the estate was divided among the tenants by the Land Commission.