The Duchall estate, as purchased by John Porterfield, embraced about half of the acreage of the parish of Kilmacolm The seat of Lyle power was Duchall Castle just outside of Kilmacolm, Inverclyde. As the stronghold of the Lyles, it was besieged by James IV, in 1498, and has almost disappeared. It was situated about two miles southwest of Kilmacolm on a detached mass of rock which was almost entirely surrounded by a deep ravine, through which ran the river Gryffe and confluent.
Kilmacolm, Scotland is a small dormitory village in the Inverclyde countryside situated between Port Glasgow and Bridge of Weir.
The few remains of Duchal Castle are to be found about 2 miles west of Kilmacolm, about half a mile south of the B788 road at Black O'Green Farm on the back road to Greenock. The Green Water and the Black Water rivers flow around either side of the Castle. There is space to park a few cars either side of the verge of the single track road which passes the Castle. It is possible to walk into what was a courtyard and then further on down a rocky path to where the Black & Green Waters meet.
The castle, about 30 yards wide by about 70 yards long and was enclosed by walled fortification since the 13th Century. Entry was by drawbridge to the north with steep sides rising from the Green & Black rivers on the east and west sides providing a further natural defence.
According to 'Metcalfe's County of Renfrew', published in 1905: "Duchall Castle, the stronghold of the Lyle's besieged by James IV, in 1498, has almost disappeared. It was situated about 2 miles southwest from Kilmacolm on a detached mass of rock which was almost entirely surrounded by a deep ravine, through which ran the river Gryffe and confluent. the sides of the rocky site to the hight of about 20 feet are either perpendicular or very precipitous. the whole position, which measures about 70 yards in length from east to west by 30 yards wide, was enclosed with a strong wall of enciente, portions of which still remain. Outside this wall to the west, the neck of the peninsula was cut across by a deep ditch. The entrance was probably at the southeast angle, where a precipitous pinnacle rose about 20 feet from the court yard. On this seems to have stood the keep, the foundations of which, surrounded by a higher wall, are yet traceable. The wall of enciente was as much stronger character than the ordinary enclosing walls of courtyards, and may possibly be the remains of a 13th century castle."