Castiglione del Lago is a town in the province of Perugia of Umbria, on the southwest corner of Lake Trasimeno. Orvieto is 59 km (37 mi) south, Chiusi is 21 km (13 mi) to the south west, Arezzo is 56 km (35 mi) to the north west, Cortona is 21 km (13 mi) to the north and Perugia is 47 km (29 mi) to the south east.

Umbria is a region of central Italy. It includes Lake Trasimeno and Marmore Falls, and is crossed by the Tiber. It is the only landlocked region on the Apennine Peninsula. The regional capital is Perugia.