Castrojimeno is a municipality in the province of Segovia, in the autonomous community of Castile and León, Spain. It is a small rural settlement in this part of central Spain.
The municipality had a population of 38 inhabitants according to the 2004 census carried out by the Instituto Nacional de Estadística (INE), making it one of the least populated places in the province.
Castrojimeno is also noted as one of the most important geosites in Segovia, a designation reflecting its significance for the study and appreciation of local geology.