Castiglione del Lago is a town in the Province of Perugia of Umbria (central Italy), on the southwest corner of Lake Trasimeno. Orvieto is 59 km south, Chiusi is 21 km to the south west, Arezzo is 56 km to the north west, Cortona is 21 km to the north and Perugia is 47 km to the south east.
Castiglione del Lago has evolved on what used to be an island - the fourth island of Lake Trasimeno, in its south west region. Over the centuries, as the town grew, the flat gap between the island and the shore was filled with piazze, houses, churches and other buildings.
The newest parts of the city are at some distance from the old, so the centro storico (historical center) of Castiglione del Lago is a well preserved medieval locality that seems to be governed by a "law of threes". In the town walls there are three gates, and inside the town there are three piazze and three churches.
- The Castello del Leone ("Fortress of the Lion") was built by Emperor Frederick II. The pentagonal-shaped castle, was completed in 1247 CE by the monk-architect Elia from Cortona.
- The Palazzo del Comune (Town Hall) was built by Ascanio della Corgna in Renaissance style, designed by the architect Vignola. It is now a civic museum and gallery.
- Church of Santa Maria Maddalena, done on a Greek-cross plan. The church has a neo-classical pronaos and, inside, a panel painted in 1580 by Eusebio da San Giorgio.