Alto del Naranjo (english)
This superb walk in the Precordillera hills from Puente Ñilhue to Estadio San Carlos de Apoquindo (or vice versa) can be done from Santiago by public transport at both ends and takes less than a day, say from 5 hours according to stopping time. It provides a rewarding hill-walking experience with excellent views of Santiago and the Andes. There is no shade or water and the vertical ascent is 850m or more. The path is easy to follow but the ascent will sort out those who aren't fit. The walk is closed on Mondays.
In your own vehicle
Puente Ñilhue is a few Km up the Camino a Farellones. A couple of hundred metres after the main road crosses the bridge itself, turn down the dirt road on the right and drive downhill for another few hundred metres to reach the start of the walk at the pedestrian bridge over the Mapocho. Parking on the road should be OK if there is space without causing an obstruction.
By public transport
Access to Puente Ñilhue is via Plaza San Enrique, just off the Camino a Farellones, reached by bus from the city centre (e.g. 411 from Los Leones). The bus calls at Plaza San Enrique soon after passing the turnoff for Farellones – move near the front of the bus so you can see the bus stop name.
Plaza San Enrique should have collectivos serving Puente Ñilhue, but none were around for me and the taxi fare seemed reasonable at CHP3,600.
Puente Ñilhue is a few Km up the Camino a Farellones. A couple of hundred metres after the main road crosses the bridge itself, turn down the dirt road on the right and get the driver to go downhill for another few hundred metres to reach the start of the walk at the pedestrian bridge over the Mapocho.
Access from the Estadio San Carlos de Apoquindo side is described in the English version of the Cerro Provincia walk: http://www.wikiexplora.com/index.php/Cerro_Provincia_%28english%29
Description of the route
Cross the river, pay the modest fee at the office if it's open (probably only at weekends), then go through the entrance gate in the stone wall (which may be locked on Mondays when the route is closed) and start the walk. The altitude here is about 1,000m.
The route is pretty clear on the ground throughout and there is little chance of wandering off the route when the visibility is good. There are periodic signs with maps showing times and distances for each stage.
Almost immediately there is a short section which uses chains to clamber up some rocks. This is not exposed and offers scope for misleadingly impressive photos. The rest of the route is walkable, the trail being rocky but firm underfoot. Fairly soon there is a junction in the path, and you take the right hand route towards Cerro Provincia and Alto del Naranjo.
The ascent is continuous, and the views of Santiago to the west and especially eastwards into the Andes get better as you climb. The spiny quisco cacti (echinopsis chiloensis) become more plentiful and taller – keep well clear of them. This stretch with the sun on your back is where all the ascent is encountered. After a good proportion of this has been scaled, a contouring irrigation canal is seen, the Canaleto de Agua, but it seems to burrow under the path somehow without being met directly. I saw eagles and possibly a swift.
The trail levels out at the top and continues southwards on the plateau (which is 1,868m high according to the route signs) on a fairly level gradient. You will eventually arrive at the obvious place for a break, the only large shady tree, a quillay (Quillaja saponaria, the soap bark tree) which the route signs say is over 100 years old. On my visit, there was a loud and ominous buzzing from the tree, as of many possibly very angry bees, so I gave that a miss and went on a bit further to the junction where the paths diverge for the summit (Cerro Provincia) and that turning west (right) down to San Carlos de Apoquindo.
It should be possible to continue southwards from Alto del Naranjo (via the summit?) and then to leave the high ground by various routes. One of these routes (with a total length of 36Km) descends to Parque Mahuida which is at the end of Av Larrain, which is the continuation of Irarrazaval and should have buses. The Parque Mahuida website has route diagrams.
From the three-way junction, the path towards Estadio San Carlos de Apoquindo starts a rapid descent, following a rough fence on the left hand side. The path is largely loose material, sand or gravel, and it is easy to loose your footing and sit down. At a point where the descent levels out a bit, look out for where the path crosses the line of the fence which you have been following on the left, at a gap which looks a bit like an English stile. It is possible to miss this (I did, and was corrected by the shouts of two Chileans some way above me).
Once the fence is crossed, the path descends into light woodland and there are no more views. The route is fairly clear and there are occasional waymark posts. The lower slopes showed the tracks of many mountain bikes, so it seems that the area could be very popular with cyclists at weekends. Following the route down through the woodland is pretty straightforward but struck me as disappointing after the inspiring views earlier in the day, but then this was in the full heat of a summer afternoon.
Eventually you will see signs to the administración and will reach the office. This was manned on a weekday, and I was invited to sign out even though I hadn't signed in there. The Spanish version of this trip says you don't have to pay to enter at this end. Finally there is a tedious trek of about a mile along a dusty road past various horse businesses to the entrance at Estadio San Carlos de Apoquindo. Here there are two sets of gates at right angles to one another a hundred metres or so apart, and the man in the outer gatehouse released the inner gates once he saw me. A couple of hundred yards beyond them is the welcoming bus stop for the 421 or CO2 to metro Los Dominicos.
Permisos / Tarifas
A fee of CHP1,500 is supposedly payable at the Puente Ñilhue entrance, but when I did the walk on a weekday in January 2013 the office was closed.
More importantly, the route is advertised as closed on Mondays, when the access gate could be locked.
Pronóstico del Tiempo
All the usual. In summer this route is hot, steep, has no shade and no water. Prepare accordingly.