Portencross has been inhabited for thousands of years. An archaeological dig found evidence of an Iron Age settlement on Auldhill, just behind Portencross Castle. The Iron Age lasted from around 800 BC to 100 BC.Portencross Castle underwent major building conservation works during 2009 and 2010 all thanks to the fund-raising efforts of the local community of Portencross and through generous donations from various organisations and the public.
Read about how it all happened.The lands around Portencross were given to the Boyds of Kilmarnock by King Robert I as a reward for their help at the Battle of Bannockburn. A number of Royal Charters were signed at the castle and it had close links with King Robert II during that period.After the 1600s, it was occupied by local fishermen. The roof was destroyed in a gale in January 1739. By the 20th century, the Adams of Auchenames owned the castle. It became a scheduled ancient monument in 1955.