Kilkea Castle is located 5 km (3.1 mi) northwest of Castledermot, County Kildare, Ireland near the village of Kilkea on the R418 regional road from Athy to Tullow. It was a medieval stronghold of the Fitzgeralds, earls of Kildare.
Sir Walter de Riddlesford built a motte and bailey castle there in 1180. A grand daughter of his married Maurice Fitzgerald, 3rd baron of Offaly, and so the Manor of Kilkea came into the possession of the Fitzgeralds and was to remain in the family for over 700 years.
Sir Thomas de Rokeby, the Justiciar of Ireland, used the castle as his military base, and died here in 1356.
The castle is particularly, associated with Gerald, the 11th Earl of Kildare known as the "Wizard Earl", who became the male representative of the Geraldines when only twelve years of age after his half brother "Silken Thomas" the 10th earl, was executed at Tyburn in 1537. The "Wizard Earl" was sent to the continent to be educated, and following his return to Kildare his interest in alchemy caused much interest among his neighbours around Kilkea Castle and he was said to possess magic powers.