Castell de Ferro, located in the province of Granada, is known principally for its tourism, its agriculture and its conservation of traditional constructions.
According to Manuel Sanchis Guarner, Castell de Ferro comes from the Mozarabic autochthonous evolution that conserves archaisms such as the non-diphthongization of the Latin letter É.
A more likely explanation is that the change from "castil" to "castell" took place between the seventeenth and nineteenth centuries when large numbers of expats returned from Catalonia accompanied by Catalans.
The word would have changed under the influence of the Catalan language which allows for the LL digraph in final position, pronounced /ʎ/ as in castell /kəs'teʎ/.
It ended up with its actual name due to the influence of the local fishermen, who pronounced Castel de Ferro.
According to the National Statistical Institute of Spain, in 2014 Castell de Ferro had 2964 registered inhabitants, representing 59.58% of the total population of the municipality.