Ballycarty House was built close to Ballycarty Castle, an ancient small square Geraldine fort that had been occupied by the Blennerhassett family after the arrival in Kerry of Robert Blennerhassett, following the grant of lands in Kerry made to his father Thomas Blennerhassett of Flimby, Cumberland, by Sir Edward Denny of Tralee in 1590. 

 

The precise location of old Ballycarty Castle is uncertain. It may have been incorporated into the later Ballycarty House, but the parts of Ballycarty watermill, whose ruins survive close by on the bank of the River Lee, appear strong enough to have been defensive - if so perhaps the old castle was adapted to become the mill.

 

During the rebellion of 1641 John Blennerhassett lived in a house within the bawn or "strong outer wall" surrounding Ballycarty Castle, this probably the same house that was later to develop into the 18th century Ballycarty House.  After 1641 the principal seat of the Blennerhassett family ceased to be Ballycarty, moving a couple of miles to the West, to the adjoining townland of Ballyseedy.

 

Blennerhassetts remained resident at Ballycarty House well into the 18th century and Agnes Blennerhassett (daughter of William Blennerhassett who rebuilt "Elm Grove", now the "Ballyseede Castle" Hotel) was born at Ballycarty on Sunday, 12th October 1740.

 

By the mid 18th century Ballycarty House was home to the Nash family (see map of 1777).