The count of Barcelona was the ruler of the County of Barcelona and also, by extension and according with the Usages and Catalan constitutions, of the Principality of Catalonia as Princeps for much of Catalan history, from the 9th century until the 18th century. After 1164, with Alfonso II of Aragon and I of Barcelona, the title of count of Barcelona was united with that of king of Aragon, and after the 16th century, with that of king of Spain.

The Principality of Catalonia was a medieval and early modern state in the northeastern Iberian Peninsula. During most of its history it was in dynastic union with the Kingdom of Aragon, constituting together the Crown of Aragon. Between the 13th and the 18th centuries, it was bordered by the Kingdom of Aragon to the west, the Kingdom of Valencia to the south, the Kingdom of France and the feudal lordship of Andorra to the north and by the Mediterranean Sea to the east. The term Principality of Catalonia was official until the 1830s, when the Spanish government implemented the centralized provincial division, but remained in popular and informal contexts. Today, the term Principat (Principality) is used primarily to refer to the autonomous community of Catalonia in Spain, as distinct from the other Catalan Countries, and usually including the historical region of Roussillon in Southern France.