The city's name derives from the Latin "Sena Gallica" (Ancient Gallia), in memory of the people who settled in the area and founded the first settlement. It is a municipality in the province of Ancona, located at the mouth of the river Misa, and extends along the coast, protected from the hills behind. It is also a famous and popular seaside resort, one of the first in Italy, active since 1853, which attracts holiday makers, thanks to its famous beach known as "di velluto" (of velvet), for the crystal clear waters of the sea, for the fantastic panorama over the Gulf of Ancona and for its modernly equipped establishments.
The first settlement was founded in 283 B.C. by the Gauls led by their commander Brennus, at war with Rome. In 295 B.C. the Romans took over the control of a vast part territory, which included the area between the river Esino and the city of Rimini, called Ager Gallicus. In 284 B.C, the Romans settled here and founded the colony of Sena Gallica, which became an important trading center for the Romans. After the fall of the Empire, the city was destroyed by the Barbarians at the orders of Alaric and later submitted, for a long period, the domain of the Byzantines. In the Middle Ages, Senigallia was proclaimed municipality and in the XIV century, it was assigned to the Papal States. During an attack by the troops of Manfred, King of Sicily, the city was completely destroyed and its walls were demolished. Subsequently in the XIV century, the city submitted the rule of the Malatesta and of the Della Rovere and in the XV century returned to be an important commercial destination.
- the Cathedral of St. Peter the Apostle, which features an imposing façade, divided into two architectural orders and delineated by pilasters. The complex was erected in the XVIII century, from designs of the architect Posi, on the ruins of a previously built church. Over the centuries it has submitted a number of restoration projects. The interior features three naves and a Latin cross plan and preserves inside a treasury of artworks;
- the Church of the Cross, built between the XVI and XVII centuries and features a façade in Renaissance style, with a rich portal, flanked by columns and surmounted by a pediment above, the interior features a single nave plan, decorated in baroque style. Inside is preserved an altarpiece by the artist Barocci;
- the Church of Santa Maria delle Grazie, which includes a monastery with two cloisters. It was built in the late XV century by Giovanni della Rovere and inside preserves an altarpiece depicting the Virgin, by the Perugino;
- the XVIII century Church of San Martino with its Baroque façade, its interior preserves a painting of the Madonna and Child with St. Anne by the Guercino and a Virgin and Child by Palma il Giovane;
- the Church of Santa Maria Assunta, built in the mid-XIX century in Neoclassical style and preserves artworks of the artist Ramazzani;
- the Church of Our Lady del Carmine and San Biagio;
- the Church of the Immaculate Conception;
- Palazzo Mastai, which dates back to the early XVII century and houses the Museum of Pius IX and the Art Gallery of Sacred Art, which features a masterpiece of the artist Palma il Giovane;
- the Rocca (the Fortress), built in the second half of the XV century, is a Renaissance square shaped fortress with four cylindrical watchtowers at each corner;
the Palazzetto Baviera, today seat of the Town Hall, is the remake of an older building, which dated to back to the previous century;
- the "Annonario" Forum, a XIX century building with an imposing character and features several lines of columns;
- the Portici Ercolani, built along the banks of the river in the XVIII century;
- the Old Town Hall from the early XVII century;
- the XVI century Duke's Palace;
- the XVI century Duke's Fountain.