County Carlow: See
Castles: there's a scrappy one in Leighlinbridge, a psychiatrically disturbed one in Carlow, a plush one near Tullow that reckons to assist the Goddess Isis, and a figment of mi'lord's imagination in Bagenalstown.
Religious buildings: the county museum in Carlow is in a beautifully preserved convent, and Carlow also has a fine cathedral. The 12th-century Old Leighlin Cathedral is still in use. Ruins include Sleaty, Killeshin and Baltinglass, but the best is Duiske Abbey across the river from Tinnahinch.
Gardens: Duckett's Grove in Carlow and Altamont south of Tullow are the best.