Great Himalayan Trail is an extreme 30-day, 1700 km trek, topping out at 5,500 m. The route takes in Entire Himalayan range; Multiple states; Months-long expedition. Best months: June–September. Watch points: Months of commitment; extreme altitude; permit complexities. Fitness level: extreme, permits required, not recommended for children under 21. Nearest hospital: Resupply towns have PHC/CHC: Munsiyari, Joshimath (best), Ghangaria (seasonal), Har Ki Dun area (Osla), Chitkul, Kasol, Manali. Between towns: zero medical facilities for 3-5 day stretches. Helicopter evacuation possible from meadows only. Comprehensive medical kit and trained first-aider in team mandatory. Network coverage: Signal at resupply towns only: Munsiyari (BSNL), Joshimath (all networks), Ghangaria (BSNL weak), Chitkul (BSNL), Kasol (Jio/Airtel), Manali (all). Zero signal for 3-7 day stretches between towns. Satellite phone MANDATORY for entire route.