Aconcagua –
The Highest Mountain in the Americas 

Mountain: Aconcagua
Route: Horcones Valley Route (Normal route) and Vacas Valley Route (360 or Polish Traverse Route)
Location: Argentina (32° 39′ 11″ S 70° 00′ 43″ W)
Altitude: 6960m (22,834ft)

At 6960m, Aconcagua is the tallest mountain in the Americas. Its South Wall is considered the most emblematic in the Southern Hemisphere.  Despite its modest description as a “trekking peak” it is an enormous undertaking. Care needs to be taken if illness and injury are to be avoided. High altitude illnesses such as AMS, HAPE and HACE are seen on a daily basis during the busiest times of the season (please refer to the UIAA Medical Commission advice on these subjects).

Given the weather conditions close to the summit, cold injuries are common too. Each year a small number of deaths occur. Many of these are altitude related and can be avoided.

This article describes ascents that offer an excellent opportunity for a safe and successful climb of Aconcagua.

Special Considerations
Permits for Aconcagua Provincial Park are only issued in Mendoza. The process requires several hours and as of 2018/19 could only be paid for in cash. Park authorities require all non-Argentinean climbers to have evacuation insurance.

Bring cash in US Dollars or Euros. Cash machines often have locally defined daily cash limits and high fees. The climbing permit can only be paid for in cash and many other services both in the city and on the mountain are more easily handled this way.

Ascent Profile – Horcones Valley Route 

[1] Horcones Station 2,950m (9,680ft)
[2] Plaza Confluencia 3,390m (11,120ft)
[3] Plaza De Mulas 4,350m (14,270)
[4] Canada 5,050m (16,570ft)
[5] Nido de Condores 5,560m (18,240ft)
[6] Colera 5,970m (19,585ft)
[7] Cerro Aconcagua 6,960m  (22,834ft)


The start of the Normal Route is situated at Horcones Station (32° 48′ 40″ S 69° 56′ 32″ W) 190km west of Mendoza on Highway 7. The start of the 360 or Polish Traverse Route is situated at Puntas de Vacas Station, 170km from Mendoza. Transfer by bus or hired vehicle can be arranged in Mendoza and takes approximately 3-4 hours. Most climbers spend the first night in one of the hotels at Los Penitentes (2,600m/8,530ft). These lie 10km from either ranger station and allow climbers to take the first steps in the acclimatisation process.

Route Description

After completing the permit check at Horcones Station you’ll be faced with a three-four hour walk to Confluencia camp. The path is straightforward and well defined. The river is crossed by a bridge, so lightweight approach shoes are ideal for the journey. Since the altitude gain is only 440m, you’ll arrive fresh and relaxed. It really is a perfect way start to the climb.

From Confluencia the path divides into two. Both are worth exploring. Many ignore the right fork and proceed directly to Plaza De Mulas Base Camp and the start of the Normal Route. However the right fork has all the ingredients for a perfect “acclimatisation day”. Not only does the route to Plaza Francia allow ready access to altitude, but at Mirador (4,000m/13,123ft) there are a series of sheltered areas that make ideal spots to spend a couple of hours acclimatising.

The following day is sometimes described as the, “second hardest day on the mountain”. Although this is an exaggeration it does give climbers an idea of what to expect. With almost 20kms of ground to be covered, not to mention 960m of ascent, the journey to Plaza de Mulas Base Camp (BC) will take between six and ten hours to complete. The majority of the walk is on established trails. However there are vaguer sections that pass through a number of small streams. These can be avoided by keeping to the right of the valley. Despite providing the only shade en route, it’s not worth lingering beside the large boulders for too long – many are used as toilets.

Finally, you’ll reach the last set of challenges – a rocky steepening and an undulating terminal moraine. There’s still 200m of vertical ascent to go and this will feel like very hard work indeed. But eventually you’ll make it, passing the Refugio Plaza De Mulas on the left before arriving tired and dusty at BC.

During the busiest time of the season, BC is nothing less than a bustling town. Several companies offer a wealth of services – meals, accommodation, showers, internet access, satellite telephone, porters and guiding services are all available at a price. In addition, rescue and medical teams also have bases here.

Once you’re established at BC you’ll need to devise an acclimatisation programme. Without this you’ll flounder on the mountain and predispose yourself to uncomfortable and sometimes life threatening high altitude illnesses.

In Mauricio Fernandez’s excellent book, “Aconcagua” he quotes Federico Reichert, an early visitor to the mountain:

“In my opinion, any person of average strength who is used to trekking at altitude can easily climb the Aconcagua to 6,500m. I have no doubts, however that the remaining 500m can only be climbed by people possessing greater energy and endurance, for the obstacles awaiting them are endless.”

It pays to take at least one day of rest before ascending past BC. For many, the next day marks the start of the load carrying process to Camps 1 and 2. However this is an enormous step. Instead, nearby Bonete Peak 5,050m (16,568ft) offers an easier alternative. The climb to the summit can be done in four hours and since little more than water and warm layers need to be carried the exertion isn’t great. After a further days rest, the real work can then begin.

A good performance above 6,500m will largely depend upon your acclimatisation programme. There are many ways to do this and everyone acclimatises at a different rate. However it’s worth bearing in mind the work of the Wilderness Medical Society (WMS). They recommend that once above a height of 3000m, climbers should sleep no higher than 500m above the previous night’s altitude and importantly, take a rest day after three to four days of ascent. The UIAA has a rich library of medical advice available on the subject.

Ascent Programme:

Day 0 Arrive at Plaza De Mulas (BC)
Day 1 Rest Day at BC
Day 2 Ascent of Bonete Peak (4,950m)
Day 3 Ferry loads to Camp 1
Day 4 Rest Day at BC
Day 5 Ascend to Camp 1
Day 6 Ascend to Camp 2 and return to BC
Day 7 Ascend to Camp 1
Day 8 Ascend to Camp 2
Day 9 Rest Day at Camp 2
Day 10 Ascend to Camp 3
Day 11 Summit Attempt
Day 12 Summit Attempt
Day 13 Summit Attempt
Day 14 Descend to BC
Day 15 Descend to Horcones Station

An interactive map of the Normal Route – produced by Grajales Expeditions –  can be found here.

Information on Camps

Canada Camp (Camp 1) sits on a rocky promontory nearly 700m above BC. The climb gives a good introduction to the mountain. The angle will remain largely unchanged from now on and the scree will become all too familiar!

“What surprised me most? Just what a massive pile of scree and unstable ground the Big A is!” BF

“Although you know it will be scree nothing can prepare you for the amount of scree… ” RWL

The first landmarks of note are the Conway Rocks which appear just after halfway. This is a popular place to stop and offers one of the few shaded spots high on the mountain. From here the site of Camp 1 is hidden, but eventually as the path climbs to the left, tents and climbers start to appear. Clean water is obtained from a nearby stream. Although the campsite is clean, the rocky edge marks the site of the toilets. Be careful when posing for photos.

After a night at Camp 1 its worth pressing on towards Nido de Condores (Camp 2). From Camp 1 the skyline above marks the halfway point and the site of Campio de Pendiente (5,300m). Although there’s a clean water supply here, few choose to stay, preferring to carry on for a further 1-2 hours to Camp 2. Although some will try to walk directly through the icefield to the campsite, the easier option is to follow the zig zags on the right and then traverse back left along flatter terrain to the camp.

A few hours spent here will be a useful aid to acclimatisation. However it’s not worth staying too long since BC is still two hours away.

Some climbers opt to wear lightweight trekking shoes up to Camp 2 or even higher. The choice is entirely personal. However, if you haven’t “worn in” your double boots, climbs to Camps 1 and 2 provide good opportunities to do it. In addition, it’s a lot easier to “surf” down the scree with double boots on, since they not only protect your ankles but they also prevent grit and stones from getting inside your socks and causing blisters.

Nido de Condores (Camp 2) is perched on the edge of a blank, windswept plateau. During the season many of the large commercial groups maintain a permanent presence there. Often, large mess tents are visible. The park authorities also maintain a small hut and several tents. These mark the last point of helicopter evacuation. During the busiest times of the year this camp sees several rescues each day. Camp 2 also marks the last source of running water. In general the water obtained at Plaza De Mulas, Canada and Nido de Condores is safe to drink. However many opt to treat the water by either boiling or adding purification tablets. As growing numbers of climbers choose to climb Aconcagua this may become standard practice in the future.

Many climbers opt to spend two or more nights resting at Camp 2, before the decision to ascend has to be made. Provided individuals are acclimatising well, the journey to Berlin Hut Camp should be a straightforward one and will take no longer than three to four hours. The nearby rock formations and surrounding mountains provide stupendous views. However the route itself is little more than a repetitive series of steep switch backs, occasionally complicated by sections of snow and ice after bad weather. Crampons and axe may occasionally be required.

Berlin Hut Camp (Camp 3) is a collection of three triangular wooden huts and enough flat ground to pitch up to 30 tents. Although the summit cannot be seen from here, the views down into the valley are extraordinary. Despite its idyllic location, the presence of rubbish and human waste can be off putting. Water is obtained from melting small patches of nearby ice. The potential for contamination is a real concern. Unfortunately when the weather deteriorates groups many find themselves here for several days. In most cases it is probably better to retreat to Camp 2 and return when conditions improve.

Summit day can be divided into three sections. First, the steep path to Independenzia, second, the traverse across the “Gran Acarreo” and third, the climb of the “Canaleta” and the final approach to the summit.

Until Independenzia the journey will have seemed a straightforward task to many climbers. However above this point, progress becomes much harder. Steps are much harder won – 1, 2, 3, even 4 breaths per step. The traverse takes longer than it first appears. Distances are dramatically foreshortened. Sometimes an hour or more is needed to reach El Dedo “The Finger”, a distinct rocky spike that marks the start of steeper ground. “The Cave” marks the start of the “Canaleta” and is ascended on the right before joining a low angled traverse back left. This is often easily spotted from below as it is usually choked full of hard packed snow. In some seasons crampons and ice axe may not be required until here, however in most years these are donned after arriving at Independenzia Hut.

Managing the final traverse is a slow and laborious process. Conditions are often difficult – high winds, driving snow and cold temperatures are not uncommon. Given the slow speed you’ll be moving at, this combination can reduce core temperature and make you very cold indeed. If you’re late you’ll be greeted with words of encouragement from descending summiteers. Whilst this is great for morale, it will slow your progress even more since the path is too narrow for two climbers to stand easily side by side. The summit plateau is protected by a short rocky steepening that is quickly overcome on the left. At 6962m, the summit is the highest point in the Americas and not a place to linger. A prompt descent is vital.

After a summit attempt most climbers opt for a night at Berlin Hut, however some parties choose to retreat all the way to BC in one push. This is a huge effort but given that sunset is sometimes as late as 2200 this is worth considering if you’re still going strong. This approach also creates an extra day that may be useful if a summit bid has been delayed by weather or poor acclimatisation.

From Berlin Hut descent to Plaza De Mulas can normally be completed in 3-6 hours. From the final long traverse into Camp 1, it is possible to leave the trail and take a more direct route towards Conway Rocks. Here, the normal path can be picked up again and Plaza De Mulas, less than an hour away, can be seen clearly below.

The journey to Horcones Station is a long one. After several days on the mountain you won’t feel your best. A rest day at BC is a very small reward and is worth taking. Make sure that you eat and drink well before making the final descent.

“On reflection the one thing that I would do differently next time would be to make sure that after summiting I had rehydrated more. I believe it would have helped especially with two long days ahead.” MS

Transport of Equipment

Mules provide the vast majority of transport needs between Horcones Station and Plaza De Mulas. This journey can be completed by the mules in just a couple of hours. Higher up the mountain it is possible to hire porters who can carry loads of up to 20kg. Fees for this service vary. However you can expect to pay up to $200 for each journey. Budget for around $600 if you want a 20kg load carried from BC to Berlin Hut Camp. It will not be possible to keep up with your porter. So don’t try.

Medical Support

During your climb you will have to undergo two medical checks. These take place at Plaza Confluenzia and BC and must be completed successfully before you are allowed to proceed. Arterial oxygen saturation, heart rate and blood pressure measurements will be taken. In addition, you will also be asked questions about long term medical problems, as well as any altitude related symptoms that you may be suffering from at that time.

For those with a history of high blood pressure it is important to have a plan formulated in case your reading is high. This may involve increasing the dose of your current medication or adding an additional drug to your normal regime. Speak to your doctor about this before you leave home.

Beware! Several individuals have been prevented from climbing the mountain as a result of high blood pressure.

Bring a spare set of medication with you in case of loss or damage.


The permit issued by the National Park Authority is for 20 days. Most will attempt the mountain in a lot less. This can create a worrying situation where poorly acclimatized climbers are making a summit attempt in less than ideal conditions simply because they are in a hurry to get up and down the peak. This article describes a programme that fits in with WMS recommendations and allows enough time for three potential summit days. The key to climbing Aconcagua is good acclimatization. This cannot be rushed!

Local Languages

Spanish. English is also commonly spoken.


Argentinean Pesos (ARS)
100 centavos = 1 Peso
US$ are also in common use.

Visa Requirements

Click here.

The stealing of foreign passports is becoming an increasingly common occurrence in Argentina.


 A Yellow Fever vaccination certificate is only required by those intending to travel north towards the forested areas bordering Paraguay and Brazil.

Malaria prophylaxis is recommended for anyone travelling in rural areas along the borders of Paraguay and Bolivia.

Like all countries in South America, Argentina has a high prevalence of Hepatitis A. Vaccination is recommended.

Climbers should check that they have completed their full courses of measles/mumps/rubella (MMR), diphtheria/pertussis/tetanus (DPT) and polio vaccinations.

Nearest Hospital

There are a number of public and private hospitals in the vicinity of Mendoza.

Follow the recommendations of the doctors on the mountain.


There are three options for evacuation: by foot, mule or helicopter.

With the permissions of the park authorities and the onsite medical staff a helicopter evacuation can be organised quickly provided weather conditions are suitable for flying. The helicopters are based at Horcones Station and can ascend as high as Camp 2 (5,560m), however weight at this altitude is a real concern and only the pilot and one passenger can be transported at any one time.

From Camp 2, BC can be reached in a matter of seconds and Horcones Station in approximately twelve minutes.

If necessary the medical staff will arrange an ambulance from Horcones Station to either a local clinic or hospitals in Mendoza. An emergency helicopter evacuation is included in the cost of the 20 day climbing permit.

In the case of minor illnesses or injuries, mules are often used to ferry individuals to Horcones Station. Although slower than helicopter, these are a safe and effective means of evacuation.

Above Camp 2, any evacuation relies upon the efforts of the climbers, guides, porters and park authorities.

In 2010 rescue equipment was placed in barrels at three locations on the Normal Route: Camp 2, Refugio Independenzia and the Canaleta. The barrels can be opened by obtaining the padlock code from the park authorities (VHF frequency 142.8KHz). A stretcher is also stored nearby which can be used to carry or slide victims down to Camp 2 or lower. Despite these developments, a rescue of a non-ambulant casualty is fraught with difficulties on Aconcagua. The combination of altitude, uneven terrain and long distances make this a slow and arduous task for rescuers. For the casualty, long periods of time spent in this environment may worsen any illness or injury.

Casualties trapped near the summit may be forced to spend a night outside. Given low temperatures, the risks of hypothermia and frostbite are a reality. This makes the chance of a successful rescue even more remote.

Individuals venturing into this part of the mountain must be able to recognise the point at which they need to turn back. An ambulant casualty has a much greater chance of survival than one who is not.

Ascent Profile – Vacas Valley Route (360 or Polish Traverse Route)

[1] Punta de Vacas Station 2,450m (8,040ft)
[2] Pampa de Leñas 2,950m (2,680ft)
[3] Casa de Piedra 3.240m (10,630ft)
[4] Plaza Argentina 4,190m (13,750ft)
[5] Camp 1 5,000m (16,405ft)
[6] Chopper Camp/Guanacos Camp 5470m (17,945 ft)
[7] Colera 5,970m (19,585ft)
[8] Cerro Aconcagua 6,960 m  (22,834ft)
[9] Plaza De Mulas 4,350m (14,270)
[10] Horcones Station 2,950m (9,680ft)

Route Description

The Vacas Valley route was originally called the False Polish Traverse but is now more commonly referred to as the 360 Route since most climbers descend via the Horcones Valley Route allowing for a complete tour of the mountain.

The Horcones Valley Route and the Vacas Valley Route both have the same level of difficulty and share the same summit day from Camp Colera (5,970m/19,585 ft). The Vacas Valley approach has two separate camps, neither of which have permanent facilities (no Wi-fi, no dining tents) and does not include an acclimatisation hike to 4000m before arriving at base camp. The route is generally less crowded than the Horcones Valley Route and because it is on the east side of the mountain gets warmed by the sun at least two hours earlier than the other side of the mountain. The Plaza Argentina Base Camp offers the same quality and kinds of service as Plaza de Mulas, except for the fact that there is no 4G cell coverage.

The permit procedure is completed at the Punta de Vacas Ranger Station after a 10km drive east from Los Penitentes. The first day´s hike is a relatively easy 5-6 hour walk to Pampa de Leñas (2.950 m/ 9,680ft). Sections of the trail are on uneven ground with protruding rocks on the trail. For those not used to this kind of terrain hiking boots are recommended rather than shoes. This part of the valley tends to be warm due to the low elevation so choose light layers to start with. And obviously take great care to protect yourself from the sun during the whole expedition. There is less UV protection the higher you go, so severe burns are a real threat.

For those on a guided expedition, the meal this first night is a real treat. You will get to experience an authentic Argentine asado (barbeque) cooked by the local mule drivers.

Unlike the Horcones Valley Route where the mules go up and down the valley in one day, on this route, if you hire mule service, you will be accompanied by the mules all three days. In the morning you will be expected to leave your equipment by 08:00 with the mule drivers. The mules will usually pass you on the way and you will have your bags waiting for you on arrival at the next camp.

The second day of the approach is one hour longer than the previous day’s hike (six to seven hours). After crossing a bridge 15 minutes out of Pampa de Leñas the valley opens into a wide corridor with beautiful views as you follow the Vacas River to Casa de Piedras 3.240m (3,240 m/10,630 ft). The trail is well marked with no major climbs along the way. Fifteen minutes before arriving at camp you will get your first awe inspiring view of Aconcagua and the Polish Glacier.

Day 3 is the hardest hike of the approach. The day starts with a frigid river crossing (those on guided expeditions will usually be crossed with mules) and then one and a half hours into the walk there is a strenuous 200m climb to a second, but much easier, river crossing. The valley leading to this first steep climb is narrow with many gullies on either side. Beware of mud slides and small avalanches should there be a big rain or snow storm the previous day. The rest of the walk continues to climb steadily but gradually. The mountain looms above you the whole day making for amazing views. Overall the hike takes seven to eight hours and ascends 950m to Plaza Argentina Base Camp (4,190 m/13,750 ft.). The long day and high final altitude leave most climbers ready for a rest the following day.

The terrain to the upper camps is generally straightforward and as is the case with the Horcones Valley how you do will depend on your acclimatisation strategy and the weather. The camps are Camp 1 5,000m (16,405ft), Chopper Camp or Guanacos Camp 3 (This was originally the third camp on a now non-existent route. Hence the misnomer. 5470m/ 17,945 ft) and Camp Colera (the word for anger not the disease. The story goes that the camp was named after a heated argument between a guide and his guest 5.970 m / 19,585 ft) which is where this route joins the Horcones Valley Route.

Of the three camps, the climb to Camp 1 is probably the most strenuous. There are two loose steep climbs along the way, a shorter one 45 minutes into the ascent and another 300m steep climb at about the three or four hour mark. Otherwise the upper camps are more challenging because of  high altitude rather than the difficulty of the trails themselves. Make sure to include several days at base camp and several acclimatisation climbs to stock camps and rest days at the upper camps into your itinerary so that you are well prepared for the 12 hour (round trip) summit day ahead. Most groups summit, at the very earliest, on day 11 of their climb. For those needing support there are porters available at base camp. Packs can weigh from 16-18kg for personal gear and above 20kg for those on unguided trips ferrying their own loads. If you are not used to this kind of arduous work at high altitude, porters can allow you to arrive at Colera Camp with much more energy than you would otherwise have for your summit attempt.

Ascent programme:

Day 0 Arrive at Plaza Argentina (BC)
Day 1 Rest Day at BC
Day 2 Load ferry to Camp 1
Day 3 Rest Day at BC
Day 4 Ascend to Camp 1
Day 5 Load ferry to Chopper Camp/Guanacos3 Camp
Day 6 Rest Day at Camp 1
Day 7 Ascend to Camp 1
Day 8 Ascend to Chopper Camp/Guanacos3 Camp
Day 9 Ascend to Colera Camp
Day 10 Summit Attempt
Day 11 Summit Attempt
Day 12 Summit Attempt
Day 13 Descend to Plaza de Mulas BC
Day 14 Descend to Horcones Station

In addition to the WMS guidelines it’s also worth bearing the following in mind for both routes:

[1] Ascend slowly – Take plenty of time to go up. If you’re breathless you’re going too fast. For much of the climb on Aconcagua you should be able to talk comfortably.

[2] Going light at first – For the first journey above BC keep your load as small as possible. Only carry a full load once you’re acclimatized. Carrying too much, too quickly will increase your risk of AMS and its life threatening complications.

[3] Looking after yourself – Make sure you have enough to eat and drink. Take regular breaks and ensure that you sleep as much as possible! Whatever happens make sure you’re comfortable enough to enjoy the mountain!

Climbing Seasons

From mid November to the end of April. During April the park authorities maintain a base at Plaza Confluencia. The remainder of the mountain is not patrolled during this time.


At least one VHF radio must be carried by all teams who enter the national park.

Mobile phone reception is only present on Highway 7.


Weather conditions in the Andes are prone to change. Nowhere are these seen more dramatically than on Aconcagua.

The approach to BC is often hot and exposed. Daytime temperatures can exceed 30 degrees C. Afternoon rain storms are not uncommon. At higher altitudes, clouds tend to gather predictably throughout the day. Mornings are often bright and clear. Poor forecasts tend to mean that cloud and precipitation arrive quickly during the morning. Following a poor forecast some groups opt to depart early and summit before midday. Whilst this may avoid the worst of the weather, the low temperatures at night (-20 to -30 degrees C or lower) increase the risk of both hypothermia and cold injury. Wind speeds of 100km/hr or greater often accompany a poor forecast.

The weather extremes on Aconcagua mean that high altitude mountaineering equipment is essential. Double boots are necessary in order to obtain a climbing permit from the park authorities. Down clothing is essential. Many climb Aconcagua with equipment suitable for much higher mountains. This is not overkill!

Water bottles are prone to freezing on summit day. Fill up with hot water prior to departure and store drinks in small quantities (less than 1 litre) close to the skin.

Get into the habit of applying a high factor sunblock (50+) regularly. Wear long sleeves, high collars and wide brimmed hats to minimize sun exposure.


At BC temperatures can reach 30 degrees C or more. Sunburn and dehydration are real concerns! However higher on the mountain temperatures can fall to below -30 degrees C! The presence of any wind will make it feel much colder. In 2010, five members of a group were evacuated by helicopter from Camp 2 after attempting to summit in poor conditions. All suffered frostbite injuries to fingers and toes despite wearing state-of-the-art equipment. When the weather is bad on Aconcagua very little can protect you! Attempting to summit in bad conditions can have life threatening consequences.

Technical Difficulty

Mainly walking, with a few scrambled steps on summit day. Climbing harness, helmet and ropes are not required. Much of the descent can be done quickly – loose scree on either side of the path makes for rapid progress!


Cases of dengue fever have recently been reported in Buenos Aires (However, in the province of Mendoza, where Cerro Aconcagua is, there is no dengue, since this disease occurs in humid areas of Argentina, such as the coast or in Buenos Aires). According to the UK’s Foreign and Commonwealth Office:

“Travellers should take extra precautions to prevent against mosquito bites. There is no vaccine to protect against dengue fever, and you should therefore use mosquito repellent regularly and cover up with suitable clothing to avoid being bitten.”

Approximately 120,000 adults over the age of 15 are infected with HIV in Argentina. This is approximately 0.5% of the adult population compared to just 0.2% in the UK.


Paper by Jeremy Windsor and George Rodway, members of the UIAA Medical Commission

Acknowledgements: The authors wish to thank Richard Hughes (RH), Mike Spencer (MS), Barry Farbon (BF), David Hillebrandt (DH), Buddha Basnyat (BB), Lucas Dauria (LD), Daniel Alessio (DA) and all those at the guiding company Jagged Globe for their help in the preparation of this article.

In early 2020, some updated information was supplied by Grajales Expeditions – Nicolas Garcia and Ilan Zeimer – principally updates to the two ascent profiles. 

All photos and video courtesy of Grajales Expeditions