Due to the proximity of Collado Villalba to the Roman Road joining Mérida and Zaragoza, the area where the town is located today underwent a Romanisation process. Some authors claim that the origin of the name would be from the Roman Villae-alba.
During the Visigoth period, the roadway inherited from Roman times continued to be used. At that time the rural area raised livestock.
The first conflicts between Madrid and Segovia date back to the 12th century over the rights to settlements in the Sierra. In the 13th century it became a Sexmo (administrative / territorial division) of Segovia until Alfonso X created the Real de Manzanares in 1332.
Collado Villalba then became the property of the House of Mendoza. Livestock, became an important feature of the area, especially nomadic grazing for cattle.
The landscape of the area defined activity for a long time. On the one hand there was an abundance of stone quarries, prairies and pasture for livestock.
In 1630 Felipe IV granted it the Privilege of “Villazgo”, on request by the Duchess of Infantado.
In the 19th century, the provincial division of mainland Spain was approved by Royal Decree on 30th November 1833. Collado Villalba was definitively included in the province of Madrid.
In 1840 the Alpedrete quarter was no longer considered a quarter of Collado Villalba, and was awarded autonomy.
According to the Pascual Madoz Geographic / Statistical / Historical Dictionary, Collado Villalba belonged to the Colmenar Viejo judicial district and to the Bishopric of Toledo, with 50 houses, including the Town Hall, school and prison.
Production was based on wheat, barley and rye; sheep, goats and cattle livestock farming, breeding of rabbits, hares and partridge, fishing for catfish and to a lesser extent, eels.
As for industry and commerce, it had a flour mill and the population was 84 residents.
The railway joining Príncipe Pío Station in Madrid and El Escorial had a stop in Collado Villalba and this much facilitated travel to the towns in the Sierra by Madrid’s residents.
Villalba was still a rural town in 1950, but from then on it underwent significant growth as a town for second homes.
In the 30’s Villalba changed from a farming community to an employment centre for services owing to different factors: The economic boost by the company MADE (Auxiliary Electricity Material) and subsequent construction of the motorway; consolidation of employment and substantial improvements to the Metropolitan Area of Madrid. This led to a significant increase in first homes in the town.