Which mountainous region of south-central Italy is located east of Campania?

The Samnium region is located east of Campania and encompasses parts of the mountainous terrain in south-central Italy. This area is characterized by its rugged landscapes, which include the Apennine mountain range that runs through the region. The historical context of Samnium is significant, as it was inhabited by the Samnites, a group known for their conflicts with the Romans.

The Apennines, while also a prominent mountain range, run through the length of Italy and do not specifically refer to a region located immediately east of Campania but rather encompass a larger area. Calabria, positioned to the southeast of Campania, extends further south and does not fit the requirement of being east of Campania. Umbria, located to the north of Campania, also misses the criteria of being east. Thus, Samnium is the most accurate choice when identifying a mountainous region directly east of Campania, highlighting its geographical and historical significance in relation to the area.