Senigallia, town and episcopal see, Marche regione, central Italy. Senigallia lies along the Adriatic Sea at the mouth of the Misa River. Founded by the Senonian Gauls in the 6th century bc, it became the Roman colony of Sena Gallica in 289 bc. In the 6th century it was one of the five cities of the Maritime Pentapolis under the Byzantine exarchate of Ravenna. After it had been destroyed by Manfredi in 1264 and rebuilt by Sigismondo Malatesta of Rimini in 1450, its lordship was assigned by Pope Sixtus IV (late 15th century) to the Della Rovere family, later dukes of Urbino. It was part of the Papal States from 1631 to 1860 and in that period was famous for its fair. Pope Pius IX was born at Senigallia in 1792. Principal buildings include the castle (1480); the Convento delle Grazie (1491), with a painting by Perugino; the cathedral (1787); and the 18th-century Ercolani Palace. Senigallia is a seaside resort, fishing port, and agricultural market and also has industries that manufacture farm tools, paper bags, and furniture. Pop. (2006 est.) mun., 44,023.