The Sierra de Guadarrama is a mountain range forming the main eastern section of the Sistema Central, the system of mountain ranges along the centre of the Iberian Peninsula. It is in Spain, between the systems Sierra de Gredos in the province of Ávila, and Sierra de Ayllón in the province of Guadalajara. The range runs southwest–northeast, extending from the province of Ávila in the southwest, through the Community of Madrid, to the province of Segovia in the northeast.