Kilbirnie Castle is a ruined 15th tower which belonged to the Barclay and Crawfurd families.

The lands of Kilbirnie were owned by the Barclay family, and it may have been them who built the first castle here. The castle takes the form of an almost square keep of four storeys, the lower two of which were vaulted. It measures around 12.8m by 9.9m on plan with walls around 2.0m to 2.5m thick.

In 1470 Sir John Barclay of Kilbirnie and Crawfordjohn died, leaving an only daughter, Marjory. She inherited her father’s estates and married Malcolm Crawfurd, son of Malcolm Crawfurd of Loudon and an heiress of Galbraith of Easter Greenock and so Kilbirnie passed into the Crawfurd family.

Around 1627 Sir John Crawfurd of Kilbirnie and Easter Greenock built a hall block projecting east from the south-east corner of the keep, measuring around 22.7m east to west by 7.7m.

The castle burned down in 1757 and was left as a ruin.