Oseja is a municipality in the province of Zaragoza, in the autonomous community of Aragon, Spain. It is a small, sparsely populated rural settlement in northeastern Spain.
According to the 2004 census carried out by the Instituto Nacional de Estadística (INE), the municipality had a population of 52 inhabitants. This figure reflects the very small scale of the community and its low population density, typical of many villages in the Aragonese countryside.
As a municipality, Oseja holds the administrative status of a local entity within the province of Zaragoza, with its own municipal governance. Its population count places it among the smallest municipalities in the region.