Villas on the Tuscany border with Lazio and Umbria
At the very edge of Tuscany this is an area rich with history, beautiful hill towns and often convenient for visitors from the US as it's around two hours from Rome airport. The main towns are San Casciano dei Bagni, Acquapendente, Piazze, Pitigliano.
Naturally warm waters bubble up in San Casciano dei Bagni, a town with wonderful spas. Pitigliano is an Etruscan town built on a narrow tufa outcrop, and has one of the oldest Synagogues in Italy. Bolsena, on the eponymous lake, has catacombs and a fantastic early medieval church.