Castile and León located on terrain feature Douro basin
Castile and León (Spanish: Castilla y León [kasˈtiʎaj leˈon] (listen); Leonese: Castiella y Llión [kasˈtjeʎa i ʎiˈoŋ]; Galician: Castela e León [kasˈtɛlɐ ɪ leˈoŋ]) is an autonomous community in northwestern Spain.
It was created in 1983 by the merging of the provinces of the historic region of León: León, Zamora and Salamanca with those of Castilla La Vieja (Old Castile): Ávila, Burgos, Palencia, Segovia, Soria and Valladolid. The provinces of Santander and Logroño, which until then had been included in the Old Castile administrative division, opted out of this merger and formed the new Autonomous Communities of Cantabria and La Rioja respectively. 
Castile and León is the largest autonomous community in Spain in terms of area, covering 94,222 km2. It is however sparsely populated, with a population density below 30/km2. While a capital has not been explicitly declared, the seats of the executive and legislative powers are set in Valladolid by law and for all purposes that city (also the most populated municipality) serves as de facto regional capital.
Castile and León is a landlocked region, bordered by Portugal as well as by the Spanish autonomous communities of Galicia, Asturias, Cantabria, the Basque Country, La Rioja, Aragon, Castilla–La Mancha, the Community of Madrid and Extremadura. Chiefly comprising the northern half of the Inner Plateau, it is surrounded by mountain barriers (the Cantabrian Mountains to the North, the Sistema Central to the South and the Sistema Ibérico to the East) and most of the territory is drained by the Douro River (Spanish: Duero), flowing west toward the Atlantic Ocean.
The region contains eleven World Heritage Sites, making it (along with Lombardia in Italy) the region with most UNESCO World Heritage Sites. UNESCO recognizes the Cortes of León of 1188 as the cradle of worldwide parliamentarism.