The castle was built in 1478 by George Maxwell when he inherited the Barony of Finlanstone
(Finlaystone). The original castle had a tower house within a walled
enclosure or barmkin entered through a large gatehouse. All that remains of the outer defensive wall is from one of the original
corner towers. It is thought that there would have been a hall and ancillary buildings such as a bakehouse and brew house
inside the walled enclosure.
The castle was enlarged by his descendent Patrick Maxwell in the 16th century. Patrick was infamous for murdering two
of his neighbours and beating his wife of 44 years who bore him 16 children.