Fuentelviejo is a municipality in Spain, located in the province of Guadalajara within the autonomous community of Castile-La Mancha. It lies in the central part of the country, in a region characterised by a sparse, rural population spread across numerous small settlements.
The municipality is small even by the standards of the province. According to the 2004 census conducted by the Instituto Nacional de Estadística (INE), Fuentelviejo had a population of 60 inhabitants. This figure places it among the least populated municipalities in the area, reflecting the broader pattern of depopulation seen in many rural parts of inland Spain.
As a municipality, Fuentelviejo holds the administrative status of a municipio, the basic local government unit in Spain, encompassing the settlement and its surrounding territory. Its small size means that its public administration and services operate on a very local scale, typical of the many minor municipalities that make up the province of Guadalajara.