Castromocho is a municipality in the province of Palencia, within the autonomous community of Castile and León, Spain. It is located in the northern part of the country, in a region characterised by the flat plains of the Tierra de Campos area.
The municipality is small, with a population recorded as 258 inhabitants in the 2004 census carried out by the Instituto Nacional de Estadística (INE). Like many rural settlements in this part of Castile and León, it is a compact village surrounded by agricultural land.
Castromocho's administrative status as a municipality places it among the numerous small local entities that make up the province of Palencia. Its population figure reflects the modest scale typical of villages in this sparsely populated region of inland Spain.