While sunlight disappears early from the deep valleys around Trongsa, the last rays linger on the dzong's sheer white walls, illuminating the small town beyond. Located high above the roaring Mangde Chu and at the junction of several important trade routes, the main trail between east and west Bhutan once passed directly through Trongsa Dzong's walls, enabling the ruling penlops to grow rich and powerful through their control of the lucrative east-west trade.
Today Bhutan's crown princes serve as Penlop of Trongsa before they ascend to the throne. For energetic visitors, it is still possible to follow the last part of the historic approach to Trongsa Dzong by walking down to the river from a viewpoint on the far side of the Mangde Chhu valley and making the steep climb back up to the western gate of the fortress. Once inside the walls, the dzong opens up into a series of courtyards — known as docheys — overlooked by colonnaded galleries and linked by long flights of stairs. Home to Trongsa's regional government and main monastic orders, the dzong houses more than twenty separate lhakhangs, with the oldest parts dating from 1543 — though many parts have been restored following an earthquake at the turn of the twentieth century.