Fuencemillán is a municipality in the province of Guadalajara, within the autonomous community of Castile-La Mancha, Spain. It lies in the central part of the country, in the region historically associated with the upper reaches of the Henares river basin.
The municipality is small and sparsely populated. According to the 2004 census conducted by Spain's National Statistics Institute (INE), Fuencemillán had a population of 108 inhabitants. This figure reflects the pattern common to many rural municipalities in inland Spain, where populations are modest and often decline over time.
As a municipality, Fuencemillán holds the administrative status granted to recognised local entities in Spain, with its own local government. Its location in the province of Guadalajara places it within the broader Castile-La Mancha region, an area of the Iberian Peninsula known for its inland landscapes and historic towns.