This place is widely regarded as one of the most picturesque places in Himachal and it derives its name from the Tirthan River which gets its origins from the Himalayan Glaciers. This river is very cold and has crystal clear water in which one can find abundant trout fish. For people interested in angling this place is a paradise as it is for hikers, trekkers and people who love to explore nature. It lies at a height of 1600 meters above sea level and it is regarded as the opening to the Himalayan National Park. Once you enter the place you should just forget the world outside and follow trails heading into the woods. There is pure bliss all around and one can opt to go for plenty of treks during their stay here. Visitors can enjoy activities such as camping, trekking, hiking and music around bonfires here.