The highway south of Trongsa initially follows the Mangde Chhu river, winding in and out of various side valleys. The highway passes the numerous access roads leading to the complex Mangdechuu Hydrolelectric project before reaching the palaces of Kuenga Rabten and Eundu Chholing. From Eundu Chholing to Zhemgang is 61km. As you drive between Zhemgang and Trongsa, keep an eye out for golden langurs swinging in the trees right beside the road. Approximately 91km from Trongsa there is a road junction at Wangduegang. Turn left and climb steeply for Zhemgang (20km) or continue along the river valley to Tingtibi (16km) and Gelephu (114km). Near the intersection and the village of Riotala, is the start or end point of the Nabji trek, where a stone pillar commemorates the settlement of the dispute between the Sindhu Raja and Naochhe that was mediated by Guru Rinpoche. Birders come to Tingtibi to pursue birds near the village of Goling