The ruins of the large courtyard style Duchal Castle lie circa 1.5 miles south-west of Kilmacolm in the Inverclyde council area and the historic county of Renfrewshire in the west central Lowlands of Scotland.

The castle stands at the bottom of the valley of the River Gryfe on a peninsula created by the Blacketty and Green Waters which have their confluence beyond the two deep gorges.

[4] Evidence of the old feudal baronial court is to be found in the place name 'Moothill' located near East Green in John Thomson's Atlas of Scotland, 1832.

[11] James IV kept and often visited one of his mistresses, Marion Boyd of Bonshaw at Duchal, having a son, Alexander Stewart with her, born in 1497 at the castle.

[3] On a visit here from Glasgow on 22 February 1497 the king commanded that money be left for Marion and his baby son giving eighteen shillings "to the noris that fosterit Marioun Boydis barne and fourteen to a harper.

[12] The castle's curtain walls follow much of the edge of the raised peninsula with its continuous precipitous and mainly vertical drop into the rivulets on either side.

On the north-eastern side is a prominent stone lined well (take care if visiting), slop shoot or garderobe gives access to the Burnbank Burn gorge and shows evidence of having been reduced in size as some stage for defensive reasons (See photograph).

[13] On the south-eastern side, overlooking the deep Blacketty Burn gorge, is a rocky outcrop that stands circa 20 ft above the courtyard floor with visible masonry foundations and this was the site of the keep, possibly a later structure of 14th or 15th century date, however too little remains to validate this.

Lord Melfort had pursued the case against the Porterfields with great vigour and he was granted the family estates which he held for a short time before they were returned and he fled the country.

Lady Duchal informed her husband who had them seized, bound and severely whipped before placing them in an old vault where they lay until an officer collected them.