At the time of Griffith's Valuation William Lancaster was leasing a property valued at £25 from the Trench estate at Ardcarn, barony of Moycarn. At the same time Thomas Lancaster was leasing a property to Capt. James Bell. In 1786 Wilson refers to Fortwilliam as the seat of Mr. Lancaster. A modern house occupies the site at Fortwilliam but there are remains of yard buildings and a walled garden.