Comillas is a small township and municipality in the northern reaches of Spain, in the autonomous community of Cantabria. The Marquisate of Comillas, a fiefdom of Spanish nobility, holds ceremonial office in the seat of power at a small castle which overlooks the town. The Comillas Pontifical University was housed here before it moved to Madrid, and the old university buildings are among the finest examples of architecture in the town. Besides this, there are many notable medieval and baroque buildings.

Comillas was the capital of Spain for a day, the 6th of August 1881, following an agreement between king Alfonso XII and the Minister's Council to gather at a formal meeting in town