Castile and León, known formally as the Community of Castile and León, is one of the 17 autonomous communities of Spain. It was constructed from Old Castile (Spanish: Castilla la Vieja) and León, first as a preautonomía—a "pre-autonomous" region—in 1978 and then as an autonomous community in 1983. It is the largest autonomous community in Spain, covering an area of 94,223 square kilometres (36,380 sq mi) with an official population of around 2.5 million (2005).

The supreme law of Castile and León, under the Spanish Constitution of 1978, is the region's Statute of Autonomy. The statute lays out the basic laws of the region and defines a series of essential values and symbols of the inhabitants of Castile and León, such as their linguistic patrimony (the Castilian language, which English-speakers common refer to simply as "Spanish", as well as Leonese and Galician), as well as their historic, artistic, and natural patrimony. Other symbols alluded to are the coat of arms, flag, and banner; there is also allusion to a regional anthem, though as of 2009 none has been adopted. April 23 is designated Castile and León Day, commemorating the defeat of the comuneros at the Battle of Villalar during the Revolt of the Comuneros, in 1521.