This hike in the mountain ridge Las Cabreras takes us initially over the Pista del Infante, which used to be the road from the reservoir of San Juan to the col of the Almenara. Next we walk via the Camino del Oso above the valley of the river Cofio, which flows into the reservoir. During a large part of the hike we have a beautiful view on the river, the reservoir and the surrounding mountains, which makes it one of the most beautiful hikes in the Sierra Oeste of Madrid.
- From the car park (1) we walk back in the direction Navas del Rey parallel to the M-501.
- At the next crossing we take the second path to the left, following the white-red marking of the GR10 (2).
- We follow the two sharp bends of the trail. Behind the second bend at the Y-junction we take the path to the left that runs further uphill (3). Here we leave the GR-10, so do not follow the red-white marking on the right.
- A fair way further on behind the cattle grid we take the Y-junction to the left downhill (4), which makes us leave the Pista del Infante and enter the Camino del Oso.
- We now follow the bend to the left and get at a Y-junction (5) where we keep right. We ignore various side trails and stay on the Camino del Oso. Also when we get past a wide path at the left (6) – closed with a barrier – we stay on the Camino del Oso.
- Eventually we reach an open space where we turn left to cross the river Cofio via a bridge (7).
- We now follow the Camino del Oso for a long time. We first walk above the valley of the river Cofio and later above the reservoir of San Juan. At a certain moment we turn to the right and walk away from the reservoir. Further on where the trail turns to the left again, we get at a junction behind the bend (8). Here we turn right onto the smaller trail and leave the Camino del Oso.
- We follow this trail for quite some time until we are under the peak of Las Cabreras (9). The last stretch there is not really a trail; we just walk between the stones towards the peak. From this top the orientation is difficult for some time as there is no trail. First we need to go straight on to descend, then keep left (towards the north) and next more to the right (towards the east), between the trees descending towards the Camino del Oso, which we can see below now and then.
- Once at the Camino del Oso (10) we turn to the left and walk back to the Pista del Infante and the GR-10 (3) via the same route as on the way out.
- When the GR-10 joins the Pista del Infante from the left and we turn right following the bend, there is a small trail (11) on the left of the road, which we can use to make a shortcut. At the end of this narrow trail (12) we turn left, and walk back to the car.