|— Comune —|
|Comune di Formello|
|• Mayor||Giacomo Sandri|
|• Total||31 km2 (12 sq mi)|
|Elevation||243 m (797 ft)|
|• Density||390/km2 ( 1,000/sq mi)|
|Time zone||CET (UTC+1)|
|• Summer (DST)||CEST (UTC+2)|
|Patron saint||Saint Lawrence|
|Saint day||August 10|
Formello is a town and comune in the province of Rome. It is located southwest of the Monti Sabatini, within the Regional Park of Veii. The communal territory is mostly composed by tuff, and is intensively cultivated.
The area has been settled since prehistoric times. As an Italian comune, it includes some of the archaeological sites associated with the former Etruscan city of Veii, north of the village of Isola Farnese, south of Formello. Settlement in the region declined after Veii's destruction in 396 BC. About 780, with newly peaceful conditions, Pope Adrian I assembled a great estate of which this territory formed part, his Domusculta Capracorum, in contrast with the power of the Abbey of Farfa, but it was destroyed by Saracen attacks in the ninth century. The domus' territories included a fundus Formellum, where a settlement developed that was first mentioned in 1027.
In the 11th century it was a possession of the Roman Basilica of San Paolo fuori le Mura, and was probably fortified in the same period. In 1279 it became a fief of the Orsini family, who sold it to the Chigi in 1661.
Main sights 
- Church of San Lorenzo (10th-11th centuries). It received a bell tower in the fifteenth century, and was renovated in 1574 with the addition of the two aisles. The left one houses frescoes by Donato Palmieri.
- Palazzo Chigi. It was built by the Orsini, probably over the pre-existing castrum mentioned in the eleventh century. It houses the Archaeological Museum of the Countryside of Veii
- Church of San Michele Arcangelo.
- The ruined Villa Chigi-Versaglia, built by cardinal Flavio Chigi in the 17th century.
- J.B. Ward-Perkins, "Etruscan Towns, Roman Roads and Medieval Villages: The Historical Geography of Southern Etruria" The Geographical Journal 128.4 (December 1962:389-404) p. 402