Congostrina is a municipality in the province of Guadalajara, within the autonomous community of Castile-La Mancha, Spain. It is a small rural settlement in the central part of the country, located in the region historically known as the Alcarria.
The municipality is sparsely populated. According to the 2004 census carried out by Spain's National Statistics Institute (INE), Congostrina had a population of 48 inhabitants. This figure reflects the pattern of rural depopulation seen across much of inland Spain, where many small municipalities have seen their populations decline over the twentieth and twenty-first centuries.
As a municipality, Congostrina has its own local administrative status within the province of Guadalajara. Its small size means it is one of many minor municipalities that make up the sparsely populated countryside of Castile-La Mancha.