Situated near Athy in the Castledermot direction stands the impressive Kilkea Castle. Built in 1180 by DeLacy the castle later became the family home to the Earl of Kildare. In 1414 the O'Moores and O'Dempseys were defeated here by the Lord Justice. The castle was rebuilt in 1426 by Lord Kildare.
In 1634, the wife of the Earl of Kildare, Elizabeth Nugent gave the castle to the Jesuits, who remained there until 1646. The castle was captured by Cromellian forces under Colonel Hewson in 1650. It was restored in 1849, having been wreaked in the1798 Rebellion.
The old church of Kilkea houses the Fitzgerald altar tomb where William Fitzgerald was buried in 1623.
There is a pagan tumulus and Christian burial ground on either side of the castle.