León is a city and municipality of Spain, capital of the province of León, part of the autonomous community of Castile and León, in the northwest of the Iberian Peninsula. It has a population of 124,303 (2019), by far the largest municipality in the province. The population of the metropolitan area, including the neighbouring San Andrés del Rabanedo and other smaller municipalities, accounts for around 200,000 inhabitants.

Founded as the military encampment of the Legio VI Victrix around 29 BC, its standing as an encampment city was consolidated with the definitive settlement of the Legio VII Gemina from 74 AD. Following its partial depopulation due to the Umayyad conquest of the peninsula. 910 saw the beginning of one its most prominent historical periods, when it became the capital of the Kingdom of León, which took active part in the Reconquista against the Moors, and came to be one of the fundamental kingdoms of medieval Spain.

In 1188, the city hosted the first Parliament in European history under the reign of Alfonso IX, due to which it was named in 2010, by the professor John Keane, the King of Spain and the Junta of Castile and León, as the cradle of Parliamentarism, and the Decreta of León were included in the Memory of the World register by UNESCO in 2013. The city's prominence began to decline in the early Middle Ages, partly due to the loss of independence after the union of the Leonese kingdom with the Crown of Castile, consolidated in 1301.

After a period of stagnation during the early modern age, it was one of the first cities to hold an uprising in the Spanish War of Independence, and some years later, in 1833 acquired the status of provincial capital. The end of the 19th and the 20th century saw a significant acceleration in the rate of urban expansion, when the city became an important communications hub of the northwest due to the rise of the coal mining industry and the arrival of the railroad.

León's historical and architectural heritage, as well as the numerous festivals hosted throughout the year (particularly noteworthy are the Easter processions) and its location on the French Way of the Camino de Santiago, which is ranked as a UNESCO World Heritage Site, make it a destination of both domestic and international tourism. Some of the city's most prominent historical buildings are the Cathedral, one of the finest examples of French-style classic Gothic architecture in Spain, the Basilica of San Isidoro, one of the most important Romanesque churches in Spain and resting place of León's medieval monarchs, the Monastery of San Marcos, an example of plateresque and Renaissance Spanish architecture, and the Casa Botines, a Modernist creation of the architect Antoni Gaudí. An example of modern architecture is the city's Museum of Contemporary Art or MUSAC.

Main sights include:

• Rayonnant gothic Cathedral. It is one of the most relevant examples of the Gothic style in Spain, almost all of it built from 1205 to 1301. It contains one of the most extensive and best preserved collections of medieval stained glass in Europe, with at least 1,764 square meters of surface, most of it containing the original windows.
• Basilica of San Isidoro, a highlight of Romanesque architecture in Spain. Built during the 11th and 12th centuries AD, the complex includes a subterranean Royal Pantheon with 12th century painted murals in an exceptional state of preservation.
• Convent of San Marcos (currently a luxurious parador) built from the 16th century AD to the 18th. Its most striking feature is a highly ornamental plateresque façade.
• Palacio de los Guzmanes, the site of the provincial diputación (parliament). It contains a patio in the plateresque style by Gil de Hontañón.
• Casa Botines, a neogothic styled building designed by Antoni Gaudí and built in 1891-1892 (one of the three Gaudí buildings outside Catalonia).
• Roman Walls, built in the 1st century BC and enlarged in the 3rd and 4th centuries AD. Long sections in the Eastern and Northern sides are preserved, as well as less complete parts in the Western side and some remains surrounded by other buildings in the Southern side. Some sections of a Medieval wall built in the 13th and 14th centuries AD also exist in the Southern side. The wall can be visited in specific locations.
• Plaza Mayor.
• Plaza del Grano.
• Barrio Húmedo (the drinking and partying area).
• Palacio del Conde Luna (14th century).
• Palacio de los Marqueses de Prado, a 17th-century Baroque building, currently the Hospital Nuestra Señora de Regla.
• Church of San Salvador de Palat del Rey, the most ancient in the city (10th century), however with few remains of the original Pre-Romanesque building. As the name (meaning church of the "Holy Savior of the King's Palace") suggests, it once acted as royal chapel.
• Church of Nuestra Señora del Merdado, from the 11th century.
• Church of San Juan y San Pedro de Renueva, dating to 1944-1970, but including an 18th-century Baroque façade taken from the ruined monastery of San Pedro de Eslonza, located about 22 km (14 mi) outside the city.
• MUSAC. It is a contemporary art museum which opened in 2005. Its design by the architectural studio Mansilla+Tuñón was awarded with the 2007 European Union Prize for Contemporary Architecture. One of the building's most distinctive features is its façade formed out of thousands of large multicolored stained-glass panels. Close to the museum is the León Auditorium, also projected by Mansilla+Tuñón, which has an equally striking presence of crisp white cubes perforated by irregularly set windows.
• Museo de León, which contains a collection of prehistorical tools and art from the Roman, Medieval and Modern periods.
• Museo Sierra-Pambley, a house from the Age of Enlightenment
• University of León.