Borasu Pass Trek

The Borasu Pass trek is a strenuous crossing of a 5,450 m pass, from Sankri in Uttarakhand over to Chitkul in Kinnaur, Himachal Pradesh. It follows an old trade route between Kinnaur and Jaunsar, so you start in the Tons basin and finish in the Baspa valley.

From Sankri a short drive takes you to Taluka, and the walk follows the Supin through tall conifer forest, past Gangaad and Osla, to the camp at Boslo, with Har Ki Dun Peak and Hata Peak hovering over the meadow. Then comes Har Ki Dun itself, a stream running through the camp, and the climb to the small lake of Maninda Tal. A morning walk into the Jaundhar Glacier region and a camp just above 4,000 m at Rataa Tho prepare the body.

After that the forest is behind you and the trail turns to glacial moraine, boulders and scree: Saun Bera at 4,540 m, a flexible reserve day, and Lamjunga at 4,870 m, the last camp before the pass.

The pass day is steep snow over scree, a view back down your whole trail, and a careful descent to the meadows of Bonga. Next day the trail drops through Rani Kanda to Chitkul, the last village in the Baspa valley, where you sleep in a hotel before the long drive to Shimla.

• Days: 10 days, 9 nights, plus a flexible reserve day.
• Grade: strenuous. Most walking days are 3 to 6 hours; the pass day is 8 to 9.
• Best months: mid-May to June and September to mid-October.
• Getting there: from Dehradun airport, with a drop at Shimla at the end. Pickup and drop included.

Nights go below 0 on the higher camps and evacuation is hard from many of them. We keep groups small and private, build acclimatisation into the days, and decide before the pass, not on it.

• Borasu Pass at 5,450 m: About 3 hours of steep snow over scree from the high camp at 4,870 m, and then a careful descent to Bonga. The one day that defines the trek.
• Sankri to Chitkul, one valley to another: You start in the Tons basin and finish in Kinnaur, on a route that served as an old trade link between Kinnaur, Tibet and Jaunsar.
• The Supin and the Har Ki Dun valley: The first days follow the river up through forest past Gangaad and Osla, with Har Ki Dun Peak (5,620 m) and Hata Peak (5,838 m) over the Boslo camp.
• Har Ki Dun camp: A meadow with a stream running through the middle and snow peaks all around, reached after a gentle climb past waterfalls.
• Maninda Tal: A small lake formed by the blocked water of the Borasu Gad, with meadows and mountains around the camp.
• Jaundhar Glacier region: A morning walk from Maninda Tal before the move to Rataa Tho, and a viewpoint from which the Swargarohini massif looks huge.
• Peaks in view: Bandarpoonch and Kalanag from Halche, and the Swargarohini massif, six peaks of which four can be seen from Sankri.
• Moraine camps and a reserve day: Rataa Tho, Saun Bera and Lamjunga are built up slowly, with a flexible day at Saun Bera before the pass.
• Two cuisines, two dialects: Sankri and Kinnaur each have their own food and speech, and the Borasu Pass connects them.
• Chitkul at the end: The last village in the Baspa valley, reached on foot from Rani Kanda, with a hotel night before the drive to Shimla.

The Borasu Pass is crossed at 5,450 m, in a single long day from Lamjunga (4,870 m) to Bonga (4,480 m). It takes 8 to 9 hours and is the hardest day of the trek. The two days before it are short on purpose: Saun Bera at 4,540 m, then Lamjunga at 4,870 m, a half-day above 4,500 m. By then the pass is only about 600 m above where you slept.

You leave early. The climb takes about 3 hours over steep terrain, snow lying on scree. From the top you can look back along the route you walked: the moraine camps, then the valley beyond. But the day is not done. The descent is careful work and stays difficult for some time. A campsite exists just below the pass, but we go on to the meadows of Bonga for the night, which are lower and kinder.

The descent on the Himachal side needs full attention. Follow your guide's line exactly, and keep your daypack light and your water within reach.

Snow or open moraine? Both seasons work, and they feel different.

• Mid-May and June: more snow cover on the climb, which can feel softer and slower, and can also mean fresh snow on the day.
• September to mid-October: less snow, more open moraine and scree, stable weather and clearer skies, and colder nights at the higher camps.

We provide microspikes or crampons and walking ice axes as the snow needs; you don't bring any. On Day 8 we use a stretch of the walk to Lamjunga for a short practice, so the pass is not your first time using them.

Decisions are made before the pass. This is a remote trek, and evacuation is not possible from every campsite. So we check everyone's health every day, and the decision to go up or wait is taken at Lamjunga, not on the slope. That is also why the itinerary holds a flexible reserve day at Saun Bera, one camp earlier: weather or a slow day can be absorbed before the high camp.

The pass day carries a lot, and you need to arrive at Lamjunga with energy left. If you walk at height regularly, you will find the logic of the previous days makes sense. If you haven't yet slept above 4,000 m, tell us; the route is better with some altitude behind you, and we'd rather say so now.

After the pass, Day 10 is an easier day of 6 to 7 hours down through Rani Kanda to Chitkul.

The Borasu Pass lies on the border of Uttarakhand and Himachal Pradesh. For a long time it was a trade route and a way for people and culture to pass between Kinnaur, Tibet and Jaunsar. Today it's walked by trekkers, but it joins the same two sides.

The Sankri side. The trek starts with a drive from Dehradun along the Yamuna and then the Tons, via Mori and Purola, to Sankri. A drive of about 7 to 8 hours. Sankri is the base for the Har Ki Dun valley; the walk begins at Taluka, a short drive on, where you meet the pack animals and the rest of the crew. The villages on the lower route, Taluka, Gangaad and Osla, belong to the Har Ki Dun valley, and the trail follows the Supin from Taluka. The people here are known for their hospitality, and the food and speech are their own.

The Kinnaur side. Beyond the pass you enter the Baspa valley. The Zupica Glacier is a source of water for the Baspa, and Chitkul (3,450 m) is the last village in the valley. The road to Chitkul has one way in, and from Chitkul to Shimla is about 240 to 250 km. Kinnaur has its own dialect and its own cooking, different from the one you left behind in Sankri. After a night in a Chitkul hotel you drive out the next morning.

Practical points for the end of the trek.

• Chitkul has no ATM, and there is no fuel after Karcham on the way out. Carry the cash you need; Sangla has an ATM and shops for basics.
• No permit is needed for Chitkul itself. Inner Line permits apply beyond it, towards the border, and are checked.
• The last day is a drive of 8 to 11 hours depending on stops and road works. Don't plan an onward train, bus or flight the same evening; give yourself the night in Shimla.

From about mid-December to March, snow often blocks the road beyond Sangla, which is another reason this is a May to June and September to October trek.

If you would like to see the Har Ki Dun valley without the pass, the Har Ki Dun trek covers it without the pass. This crossing is for those who want to carry on across.

Before the high ground, the Borasu Pass trek spends four days in the valley, and they are walked at an easy pace. Each day ends at a camp with its own character.

Days 2 and 3: the Supin and the climb to Boslo. After the drive to Taluka, the walk is gentle, following the Supin through Gangaad (2,400 m) to the camp at Chillud Gad (2,500 m). The next day passes Osla (2,700 m) and Halche (2,900 m). Near Seema we cross the suspension bridge to the true left of the river, and the path follows it up towards Kalkati Dhar. A few sections are steep. From Halche you can see the twin peaks of Bandarpoonch and Kalanag. The camp at Boslo (3,150 m) has Har Ki Dun Peak and Hata Peak hovering over the meadow, in dense forest, with the river far below, heard rather than seen.

Day 4: Har Ki Dun to Maninda Tal. The climb to Har Ki Dun (3,600 m) is gentle, past a few waterfalls and openings in the forest. At Har Ki Dun a stream runs through the middle of the meadow, with snow peaks around it. We spend some time there and then continue to Maninda Tal at 3,800 m. It is a small lake, formed by the blocked water of the Borasu Gad, with meadows and mountains around it.

Day 5: the Jaundhar Glacier region. In the morning we walk into the Jaundhar Glacier region, return to camp before lunch, rest, and then move on to Rataa Tho, sleeping a little above 4,000 m. This is the day that does the most for the pass. The Swargarohini massif, six peaks of which four can be seen from Sankri, looks huge from the Jaundhar viewpoint, and from the Har Ki Dun camp.

Rataa Tho is the first night above 4,000 m. If you feel a headache or poor appetite, tell your trek leader that evening.

If the lake and the peaks above the Tons basin interest you, Har Ki Dun and Ruinsara Tal takes you into the neighbouring valley without a pass. The route beyond Rataa Tho is moraine and scree, which is a very different walk from the forest and meadows of the first days.

The Borasu Pass trek is graded strenuous. The trail has steep ascents and descents, most walking days are 3 to 6 hours, and the pass day is 8 to 9. On Day 10 the walk down to Chitkul takes 6 to 7 hours. From Rataa Tho onward you sleep at 4,000 m or higher, and on the higher camps the temperature goes below 0. It is remote, and not every campsite can be evacuated from easily.

What it asks of you.

• Fitness: good fitness and regular cardio in the weeks before. The days are long and the trail steep.
• Altitude familiarity: it helps to have slept high before. The sleeping altitudes run 4,000 m, 4,540 m and 4,870 m on the last nights before the pass.
• Patience: the days before the pass are short, and the reserve day is there for use, not to be skipped.

The season. The pass is crossed from mid-May to June and from September to mid-October. In spring the high passes in this belt open once the snow recedes, and there can still be snow on the climb. In autumn the moraine is open, the weather more stable and the skies clearer. Both seasons work. From about mid-December to March, snow often blocks the road beyond Sangla, so winter is not a season for this trek.

How it compares. The Bali Pass trek crosses a lower pass, at 4,850 m, to Yamunotri, and the Dhumdhar Kandi Pass trek is another high crossing in this region. Borasu, at 5,450 m, takes you out of Uttarakhand altogether, into Kinnaur. If you haven't yet done a pass, a lower one is the better start.

What it teaches. This is a good trek for learning how to walk well at height: short days into the high camps, climbing high and sleeping a little lower, walking on snow with the gear we provide after a short practice, and accepting your guide's decision on pass day. These are the same habits that carry over to the bigger passes and to peaks.

Tell us the treks you have done and how you walk at height, and we will say plainly whether the Borasu Pass is the right next step for you, or whether another route should come first.

The Borasu Pass trek takes 10 days with a flexible reserve day. It starts at Dehradun airport and finishes with a drop in Shimla, with pickup and drop included. The schedule is built round the pass, and each part is placed for a reason.

• Days 2 to 4 in the valley. The first days follow the Supin to Chillud Gad, Boslo and Har Ki Dun, and end at Maninda Tal at 3,800 m. The days are 4 to 6 hours, and the camps are low, among forest and meadows.
• Day 5, the key day. A morning walk into the Jaundhar Glacier region, then a move to Rataa Tho at about 4,000 m. This is the most important day for the success of the trek.
• Days 6 to 8, short days at height. Saun Bera (4,540 m) and Lamjunga (4,870 m) are kept to 3 to 5 hours, so you arrive with energy left.
• A flexible day at Saun Bera. It sits before Lamjunga, so weather or a slow day is absorbed before the last camp.

Acclimatisation is built in, and the trek leader checks everyone's health every day. If someone is unwell, the decision is taken before the pass.

Camps and team. You sleep in a hotel in Sankri and Chitkul, and camp in between. The pack animals and the crew meet you at Taluka, and the crew is local and paid fairly. We carry our waste down. Across our treks we have had zero fatalities and zero injuries since inception. That is kept by discipline, not luck, and the discipline includes turning back when it is the right call.

Getting in and out. The drive from Dehradun to Sankri is about 190 km and 7 to 8 hours, so it takes the whole of Day 1. On Day 11 the drive from Chitkul to Shimla is about 245 km and 9 to 10 hours, with road works possible. Because that day fills most of daylight, we suggest planning your onward journey from Shimla for the next day.

Who it suits. Fit walkers who like an unhurried pace, a small private group (usually 2 to 10) and a guide who decides by conditions and not by the clock. If you want a fast schedule or a large group, this isn't that trek.

Tell us your dates, your trekking experience and how you walk at height, and we will shape the days around you.