Marche, region in central Italy fronting on the Adriatic Sea and comprising the provinces of Ancona, Ascoli Piceno, Fermo, Macerata, and Pesaro e Urbino. A region of mountains and hills, its only pieces of level land are scattered along river valleys and on the Adriatic shore northwest of Ancona. Its mountain backbone is the Umbrian-Marchigian section of the Apennines, rising to 8,130 feet (2,478 metres) at Monte Vettore. The administrative boundary between Marche and neighbouring Umbria, on the west, is the watershed between the Tyrrhenian and Adriatic slopes.

Except for the northernmost part, the hills of Montefeltro, Marche is crossed by numerous rivers running from the Apennines east to the Adriatic; the most important are the Metauro, Foglia, Esino, Potenza, Chienti, and Tronto. In their upper sections these streams flow through narrow valleys and some deep gorges. In their lower sections they widen, and the valley floors are intensively cultivated, most of the lower slopes either in meadows or in well-tended fields.

The region, originally inhabited by the Gauls and the Picenes, was early incorporated into the domain of Rome and became a single administrative unit as early as 292 ce. During the early Middle Ages the southern part was ruled by the Lombards; the northern section, the Maritime Pentapolis (Rimini, Pesaro, Fano, Senigallia, and Ancona) on the Adriatic coast, was controlled by the Byzantine exarchate of Ravenna. The modern name appeared during the 10th century when the region was divided into the imperial marches (border provinces) of Ancona, Camerino, and Fermo; shortly afterward numerous communes constituted themselves into independent units. With the emergence in the 12th and 13th centuries of such powerful feudal families as the Montefeltro of Urbino and the Malatesta of Pesaro (and Rimini), turbulent times set in—aggravated by the desire of the popes to reestablish their temporal authority, nominal in the area since the 8th century. This process, begun in the 14th century, was completed with the incorporation of the duchy of Urbino into the Papal States in 1631. Marche became part of the Kingdom of Italy in 1860.

Manufacturing forms the basis of the economy, with services, particularly tourism, growing in significance. Among the most important regional manufactures are domestic appliances, footwear, clothing, and furniture. More traditional products include ships, paper, musical instruments, and pottery. Agriculture has declined in importance, although viticulture remains notable, as does the fishing industry, which operates out of several of the Adriatic ports, particularly San Benedetto del Tronto and Ancona, the capital and principal port. The main artery of northwest-southeast traffic is the coastal railroad from Bologna to Foggia and Bari; also, a direct rail line runs from Ancona to Rome. Area 3,743 square miles (9,693 square km). Pop. (2010 est.) 1,577,676.