Campoo is a comarca (district) of Cantabria (Spain) located in the High Ebro. With an area of slightly more than 1,000 km2, it includes the municipalities of Hermandad de Campoo de Suso, Campoo de Enmedio, Campoo de Yuso, Valdeolea, Valdeprado del Río, Valderredible, Reinosa, Las Rozas de Valdearroyo, Santiurde de Reinosa, Pesquera, and San Miguel de Aguayo. The local inhabitants are called Campurrians . Its highest elevation is the Cuchillón peak, and the lowest is Pesquera, with the capital, Reinosa at 850 m.

Cantabria is an autonomous community and province in northern Spain with Santander as its capital city. It is called a comunidad histórica, a historic community, in its current Statute of Autonomy. It is bordered on the east by the Basque autonomous community, on the south by Castile and León, on the west by the Principality of Asturias, and on the north by the Cantabrian Sea, which forms part of the Bay of Biscay.