Municipality in Castile and León, Spain
Castrillo de Onielo is a municipality located in the province of Palencia, Castile and León, Spain. According to the 2018 census (INE), the municipality has a population of 101 inhabitants.
References
41°51′N 4°18′W / 41.850°N 4.300°W / 41.850; -4.300