Castillejo de Mesleón is a municipality in Spain, located in the province of Segovia within the autonomous community of Castile and León.
It is one of the many small municipalities that make up the province of Segovia, a largely rural area of the Castilian interior in north-central Spain. As a municipality, Castillejo de Mesleón forms the basic unit of local administration in Spain, with its own local government.
Detailed information about the village's population, history, and landmarks is limited; its principal administrative identity is as a Segovian municipality within Castile and León.