In the 1870s William Johnstone of the Rent Office, Williamstown, county Galway, owned 584 acres in the parish of Templetogher, barony of Ballymoe, part of the estate of the McDermotts of Springfield at the time of Griffith's Valuation. He purchased his Williamstown estate from the Connollys in 1860. William Johnstone had a brother Captain John Johnstone, who owned an estate in county Cavan. William Johnsone's nephew Robert Henry succeeded to both the Williamstown and county Cavan properties. Robert Henry Johnstone was also a land agent and by the early 20th century controlled a number of estates in both counties Galway and Cavan. A strong supporter of the Orange Order he became heavily embroiled in disputes with tenants over land ownership. William Keaveney has written a book about Johnstone's treatment of tenants on his wife's estate at Aughrim and his own estate at Williamstown, county Galway. This surname is sometimes spelt Johnston in historical records.