Borasu Pass Trek

This particular Borasu Pass itinerary approaches one of the Himalaya's historic trade crossings from its Uttarakhand side, starting in the Tons valley rather than from Chitkul in Kinnaur, and the drive up from Dehradun is where guides typically establish just how significant this route once was for trans-Himalayan trade. The road follows its usual path through Mussoorie and into the Yamuna valley, past Barkot's orchards and on through Naugaon and Purola, before narrowing toward Mori and the Tons river gorge that leads eventually to Sankri. Historically, Borasu Pass connected traders and shepherds moving between the Tons valley and the Baspa valley on the far side in Himachal's Kinnaur district, a route that predates any formal trekking industry by centuries and carried salt, wool, and other goods across one of the range's more demanding high passes. Guides spend real time on this drive distinguishing the Uttarakhand approach from the shorter, more commonly attempted Kinnaur-side version of the same crossing, noting that starting from Sankri means several additional days of valley walking before the technical high-altitude terrain even begins, a fundamentally different experience from starting closer to the pass itself on the Himachal side. The Govind Pashu Vihar Wildlife Sanctuary checkpoint near Netwar processes the necessary permits, and given the trek's extended duration and eventual exit into a different state entirely, paperwork here is more involved than for shorter treks through the same valley. Sankri, reached by late afternoon, hosts the final equipment and logistics briefing, covering everything from the extended food and fuel supplies needed for a week-plus expedition to the rope and glacier-travel gear required for the pass itself, a considerably more serious undertaking than the shorter Har Ki Dun or Ruinsara treks sharing this same trailhead village.

The opening walking stage follows the same well-trodden Supin valley trail used by the region's other major treks, but for a group bound eventually for Borasu Pass and a descent into an entirely different state, this stretch carries a distinct sense of being merely the first leg of a much longer journey. From Taluka, the trail moves steadily alongside the Supin river through deodar and pine forest, cantilever bridges crossing the water at intervals and terraced fields breaking the tree cover near scattered points where the valley widens enough to support them. Osla village, visible on the far slope with its stacked wooden houses and the Someshwar temple linked to Duryodhana in local tradition, offers the same natural pause point it does for every trek through this valley, though guides on the Borasu itinerary often use the moment to remind the group how much further this particular route still has to travel before reaching genuinely committing terrain. Historically, traders moving goods across Borasu Pass would have passed through or near this exact stretch of trail, making the valley's current role as a trekking corridor a direct continuation of a much older function as a transit route between different sides of the range. Seema, reached in the afternoon, offers the first proper camp, and the pacing here, while similar in physical terms to other treks starting from the same trailhead, is set with an awareness of the considerably longer road ahead, guides generally favouring a measured, sustainable rhythm over pushing hard on what is, in the context of this particular expedition, still a relatively easy opening stretch.