Eastern Bhutan is different from western and central Bhutan in terms of development and lifestyle, and if you enjoy seeing the countryside, then it's well worth the long haul to get there. The steepness of the region lends itself to some spectacular views, with rushing waterfalls and fantastic landscapes. The small towns in some districts tend to be built on the hillsides instead of in the valleys, and the dominant language is Sharchop kha, unlike in the rest of Bhutan, where the dominant language is Dzongkha which is the official language. In addition to the various sights in eastern Bhutan, each district has its own beauty and it's way of simple and happy life.  

The drive from Bumthang to Mongar is an exhilarating eight hours, particularly the Thrumshing La (pass) at an altitude of 3,750 meters. Mongar's main attraction is the Mongar Dzong, which is more modern than most dzongs in Bhutan (though architecturally it looks the same), having been built under the guidance of the Third King of Bhutan in 1953.

Lhuntse is about a three hours drive north of Mongar. It's an isolated region and is mostly rural. The landscape consists of stark cliffs, gorges, and thick forests. The Lhuntse Dzong is worth seeing for its beauty and location--it overlooks the Kuri Chu valley. Lhuntse is also famous for producing the local handmade silk materials for Gho and Kira (the national dress) and bamboo basket-making.

Roughly three hours east by car from Mongar is Trashigang, which is the largest town in eastern Bhutan. There are many sights to see in and around Trashigang, including monasteries, temples, a weaving center, a school for the blind, and Sherubtse College, which was the first college in Bhutan. While the town is small, there are still some variety of local restaurants.  A visit to the Trashigang Dzong is a must.

An interesting sight in the region is Chazam (iron bridge), a 73m-long trail suspension bridge. Originally there was a iron chain bridge here, which was built by a Tibetan iron chain bridge builder called Thangtong Gyalpo in the 15th century. The remains of the iron chain bridge can still be seen today while some parts of the chain are displayed in the Trashigang Dzong. Just a few kilometers from Trashigang is an interesting temple called Gom Kora. Situated behind the temple is a large black rock. It is said that Guru Rinpoche meditated in a cave in the rock and that you can see the impression of his thumb, his hat, and his body on the rock. Every spring people from all over eastern Bhutan, including nomads, circumambulate the temple and the rock throughout the night. About 2 kilometers from Gom Kora is an abandoned iron chain bridge behind the village of Duksum. It is said that this is the last remaining iron chain bridge built by Thangtong Gyalpo.

Tashiyangtse District makes a nice day excursion from Trashigang. It's a small, pretty, quiet town. The people of this district are famous for making wooden bowls and containers, which are said to be the best in Bhutan. Just below the town is the Chorten Kora. Every year a great two-day festival is held there. People from Arunachal Pradesh in India, on the other side of the hill, come for the first day of the festival to honor one of their local deity. The second day of the festival is for the Bhutanese, and people come from all parts of eastern Bhutan to witness the mask dances and be blessed. An hour's walk from Chorten Kora is a village called Bomdeling, where the black-necked cranes spend the winter here for roosting.