The Val di Chiana (or Valdichiana) is a valley of alluvial origins of central Italy. It is located in Tuscany, between the provinces of Arezzo and Siena. The valley lies in a north-south direction between the Basin of Arezzo and the Plain of Orvieto, covering the entire catchment basin of the Canale Maestro della Chiana, the main waterway flowing from Lake Chiusi.