Trashigang Dzongkhag shares its border with the Indian state of Arunachal Pradesh in the east. It is 551 km away from Thimphu and is one of the largest Dzongkhags in the Kingdom. The altitude elevation ranges from 600 m to over 4500 m above sea level. The climate is mainly temperate with annual rainfall between 1000 mm and 2000 mm.
This Dzongkhag has a total area of 2204.5 square kilometers. It has a total of 8,610 households with a population of over 71,768. The density of the population is 33 per sq. km. The forest cover accounts for 77.87 percent of the total and the Dzongkhag has arable land of 3.64 percent of its total area.
The Dzongkhag Administration Headquarters and the main town are located at Mithidrang, which falls under Samkhar Gewog. The Dzong is used as the Dzongkhag Headquarters and also as the seat of Dzongkhag Rabdhey.
The Trashigang district divides into 3 sub-districts, 15 village blocks, and 79 small villages, including an urban center. All village blocks except Sakteng have motorable roads.
Constructed in 1659, the fortress sits atop a cliff with steep sides on three sides overlooking the Drangme Chhu and Gamri Chhu rivers. Zhabdrung Ngawang Namgyal prophesied the construction of the Dzong and ordered Chhogyal Minjur Tampa, the Penlop of Trongsa, to build it and subdue local chiefs. Legend has it that the Dzong’s sight caused an invading Tibetan army to retreat, calling it a “sky fortress.” Gyalsey Tenzin Rabgye expanded the Dzong in 1680-1694, and Dzongpon Dopola expanded it in 1936. Consecrated and named Trashigang by Dudjom Jigdral Yeshe Dorje. After the 1962 Sino-Indian War, Bhutan let Indian soldiers returning home pass through the east, but they had to leave their rifles in the Dzong’s armory and proceed unarmed. The rifles remain there today. The four-day Trashigang Tshechu festival is celebrated by fifteen Gewogs every year.