San Agustín del Guadalix is a Spanish town located north of the Comunidad de Madrid, near to Sierra de Guadarrama. It is bordered by Pedrezuela to the north, the municipalities of El Molar and Algete to the east and Colmenar Viejo to the south and west. The origin of the town is obscure, but it appears that it was settled by the Iberians in the pre-Christian era.