Alcalá de Henares (Spanish pronunciation: [alkaˈla ðe eˈnaɾes] ) is a Spanish municipality of the Community of Madrid. Housing is primarily located on the north bank of the Henares. As of 2018, it has a population of 193,751, making it the region's third-most populated municipality.
Predated by earlier hilltop settlements (oppida) and the primitive Complutum on the left bank of the Henares, the new Roman settlement of Complutum was founded in the mid 1st century on the right bank (north) river meadow, becoming a bishopric seat in the 5th century. One of the several Muslim citadels in the Middle March of al-Andalus (hence the name Alcalá, a derivative of the Arabic term for citadel) was established on the left bank, while, after the Christian conquest culminated c. 1118, the bulk of the urban nucleus returned to the right bank. For much of the late middle-ages and the early modern period before becoming part of the province of Madrid, Alcalá de Henares was a seigneurial estate of the archbishops of Toledo. Under patronage of Francisco Jiménez de Cisneros, Alcalá was transformed into a college town in the 16th century in the wake of the creation of the University of Alcalá.