Jesi a.k.a. Iesi is a town and comune of the province of Ancona in the Marche, Italy.
Now a quiet agricultural and commercial center in the floodplain on the left (north) bank of the Esino river 17 km before its mouth on the Adriatic, it was for several centuries the capital of a small independent city-state, and it retains a striking circuit of medieval walls, as well as a castle restored and extended by Baccio Pontelli
Jesi was the site of the birth of Holy Roman Emperor Frederick II in 1195.
- The Cathedral (Duomo), built in the 13th-15th centuries. The façade and the Latin cross interior are modern.
- Palazzo Balleani, an example of local Baroque architecture, built from 1720 and designed by Francesco Ferruzzi. The façade has a characteristic blacony supported by four atlases (1723). The interior has precious gilted stucco decoration.
- The convent of San Floriano (18th century).
- The 14th century walls, built following the line of the Roman ones. Six towers remain today.
- Church of San Marco, just outside the historical centre. A Gothic architecture, it was erected in the 13th century. The interior has a nave and two aisles, with a 14th century fresco of Rimini's school.
- Palazzo della Signoria (late 15th century).
- Palazzo Ricci, finished in 1547. The diamond-like bricks of the façade are inspired to famous Palazzo dei Diamanti in Ferrara.
- Teatro Pergolesi, built in 1790.
- Palazzo Pianetti, one of the most outstanding examples of Italian Rococo art. The wide façade has exactly one hundred windows, while the interior has a noteworthy giardino all'italiana. The palace houses city's civic art gallery, with a series of paintings by the Venetian artist Lorenzo Lotto.
- The church of Santa Maria delle Grazie (15th century). The belltower is from the 17th century.
- The 13th century church of San Nicolò. It has a Romanesque apse and a Gothic portal.
Natives of Jesi