From the south end of the Kullu Valley, the Tirthan Valley leads up southeast into the region known as Inner Seraj. This is an area of exceptional valley and mountain scenery, unspoiled villages and nature, great walks and inviting guesthouses. It's becoming known among Indians seeking a low-key escape from the plains, but is still off most foreign visitors' radar. It's the gateway to the spectacular, World Heritage–listed Great Himalayan National Park, 754 pristine square kilometres of steep-sided river valleys and mountains reaching right up to the 6000m-plus peaks of the Great Himalayan Range.
Inner Seraj has two main valleys – that of the Tirthan River itself, and the Banjar Valley which rises southward from the small town of Banjar. The Banjar Valley climbs to the 3132m Jalori Pass, which leads over to the Sutlej valley and thus forms the most direct route linking the Kullu Valley with Kinnaur.