El Gasco Dam – Mirador Las Marías loop from Torrelodones

01:21

11.4km

280m

Running

Moderate run. Good fitness required. Mostly runnable paths. Some sure-footedness required. The starting point of the route is accessible with public transport.

Last updated: October 8, 2026

Tips

Your route passes through protected areas

Please check local regulations for:

Parque Regional de la Cuenca Alta del Manzanares

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Start point

Bus stop

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275 m

The El Gasco dam, also called Peña Strait or Carlos III Dam, is one of the most important civil engineering projects in 18th century Spain. It is located above the Guadarrama River gorge, in an area currently protected by the regional park of the middle course of the Guadarrama River and its surroundings.

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5.38 km

View of the El Gasco Dam and Guadarrama River Valley

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The El Gasco dam is an unfinished dam, built at the end of the 18th century (between 1787 and 1799), on the Guadarrama River. Its ruins are located at the confluence of the municipalities of Torrelodones, Galapagar and Las Rozas de Madrid, in the northwest of the Spanish autonomous community of Madrid.

It was designed by the Spanish military engineer, of French origin Carlos Lemaur, promoted and financed by the Bank of San Carlos, under the Royal Treasury of Carlos III, in the context of the works of the Guadarrama canal, which was not completed either. , of what would have been its regulating reservoir. Through this project, it was intended to create a navigable channel of 667 km, which, saving a difference of 700 m, would have linked Madrid and the Submeseta Sur with the Atlantic Ocean, connecting the waters of four main rivers: the Guadarrama (its point of origin), the Manzanares (at the height of the Toledo Bridge in Madrid), the Tagus (as it passes through Aranjuez) and the Guadalquivir (through Seville).
Source: es.wikipedia.org/wiki/Presa_de_El_Gasco

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