Barretstown Castle is a castle in Ballymore Eustace, County Kildare, Republic of Ireland. It stands on the site of a late 12th century Anglo-Norman castle.
The first historical mention of the place is in a 1547 inquisition held after the Dissolution of the Monasteries, when Barretstown Castle was listed as the property of the Archbishop of Dublin, from whom it was promptly confiscated by the Crown.
Since that time, the Castle was held by the Eustace family on a series of "permanent leases." Early in the 18th century the Borrowes family acquired the estate, and retained possession for some 200 years.
Unlike the Eustace baronets of the 16th and 17th centuries, the five baronets who spanned the 19th century played no part in public life. This quiet aristocratic reign ended with the flamboyant Sir Kildare, 10th Baronet (1852-1924), whose father Rev. Sir Erasmus, 8th Baronet, had significantly modified the residence in a medieval, romantic, asymmetrical style.
In 1918, the Borrowes family having left Ireland, Barretstown was purchased by Sir George Sheppard Murray, a Scotsman who converted the estate into a fine