In 1472 Chinchón had 127 "pecheros"(commoner) or 635 neighbors to an estimated average of 5 neighbors - 1 commoner. In the forming of census vassals in 1480, ordered by the Catholic Monarchs, it was found that there were 281 or 1405 vassals neighbors.
In 1782 had 916 households, 1,200 families and 4,000 inhabitants. In 1847 there were 4,886 residents and in 1,849 it can be counted 5,288 scores neighbors. In 1920 the population in fact was 5074 and in 1940 year there were 4,899 inhabitants.
The 1996 municipal census population scores around 3,849 while the figure for 1993 is 4,053.
Since the last third of the nineteenth century is a trend that is very pronounced backward from 1940 in which there is severe emigration and a sharp drop in population.
The Municipality has been depopulated of young people seeking better working conditions, study and life, resulting in an aging population over the soil itself by nursing homes and homes for the elderly Chinchón installed in offering their services to the region.
The proximity of Madrid has led to migration from rural to urban.
The population is heavily concentrated in the urban area with a population density of 46 inhabitants per km2, which is less than half the national population there is also dispersed in the Tajuña Vega and some urbanization of the suburbs.
Since 1998 the trend changed and gradually increases the population due to housing prices in the big city, from the place of origin and especially the immigrant population settled in the town in recent years, 354 foreigners registered at the end 2002, has made the population is maintained, even grow, resulting in the figure of 4,666 residents in the last census in 2003 proposal.
The immigrant population according to data from January 2011 (varies due to ongoing reviews of pattern and mobility of these people) is of 829 residents of 40 different nationalities, corresponding to 15.51% of the registered population (data Madrid place this population at 16.72% of total).