Hugh Kennedy of Ardstinchar — who had fought in France for Joan of Arc — built this castle in the 1420s on a rock above the mouth of the Stinchar, and for nearly two centuries it was the seat of the Bargany line of the Kennedys.
That made it one pole of the feud that dominated Carrick through the late 1500s: the Bargany Kennedys here and at Bargany against the Cassillis Kennedys at Dunure and Culzean. It was a Kennedy of Bargany who stormed Dunure in 1570 to rescue the Commendator of Crossraguel from being roasted — and it was the killing of a young laird of Bargany near Maybole in 1601 that finally ended the feud, and with it this castle's importance.
Mary Queen of Scots is said to have stayed here in 1566 on her way to Whithorn.
What survives
Not much, and that is part of the effect: a single shattered wall of tower standing on its crag, visible from the A77 as you cross Ballantrae bridge, gaunt against the sky. Stone from the ruin was taken for the bridge and for village buildings, which is why so little is left.
It is free and open access, but the ruin is unmaintained and unstable. Look at it from the outside — there is nothing inside worth the risk of loose masonry.
Visiting
Park at The Vennel in Ballantrae, which has toilets, and walk up. Twenty minutes covers it.
Combine with the shingle spit and lagoon at the river mouth, the coastal path stage to Lendalfoot, and for the wider story, the Kennedys of Carrick. Twelve minutes south of Girvan.