The route leaves Guadarrama and climbs the N-VI to the Alto del León. It drops down the Segovia side to San Rafael and continues on the N-603 towards Segovia. From there it takes the CL-601, runs through the Valsaín pine forest and climbs the range again over the Puerto de Navacerrada, before descending on the M-601 to the village of Navacerrada.
It is a full loop around the range, crossing the municipalities of Guadarrama, El Espinar, Otero de Herreros, Ortigosa del Monte, La Losa, Segovia, the Real Sitio de San Ildefonso, Los Baldíos and Navacerrada. It combines two passes of different character: the Alto del León, with a broad layout, and Navacerrada from the Segovia side, with the Valsaín stretch through the pines. In between, the northern face of the range gives a different view of the mountains you see from Madrid.
It is about 76 km and just under an hour and a half without stops, with more than 100 bends and four hairpins. Altitude ranges from about 960 m to 1,861 m. The N-VI and N-603 have long, fast stretches: stick to the limits and take care with lorries and cars when overtaking. The climb to Navacerrada has heavy traffic and many cyclists at weekends.