Strategically built on a projecting ridge with deep gullies, the Simtokha Dzong overlooks and commands the entire Thimphu Valley.
Zhabdrung Ngawang Namgyel was one of the greatest builders of Dzongs in Bhutan. To consolidate his newly acquired domain in western Bhutan and to defend himself from both the internal foes and external enemies he started constructing Dzongs, beginning with the Simtokha Dzongs.
The present place where the Dzongs stands is the boundary between common to three western regions: Sha (wangduephodrang), Wng (Thimphu) and Pa (Paro). The intersection was marked with three stones that belong to the people of Punakha, Thimphu, and Paro. Surrounded by these three stones was a piece of land known as Sem-tokha or Sem-dokha with a temple built on it. This temple was later gifted to Zhabdrung by Lama Pangka Shong. History says that a Tibetan Lama Zhang has prophesied that Zhabdrung Ngawang Namgyel would build a Dzong at the junction of three western lands. To fulfill the prophecy and honor the offer of Lama Panka Shons, Zhbdrung decided to build the Dzong.
The area was inhabited by many demons, and legend has it that the site where Zhabdrung decided to build the Dzong was occupied by a demon that would harm travelers who often stayed during the night. Zhabdrung visited the place and subdued the demon, banishing her into the rock on the hill where the present Dzong is located. The Dzong was constructed enclosing the rock, to ensure the continuing imprisonment of the demon. Hence the dzong derived its name as Simtokha, from the word sunmo (demon), do (stomach) and kha (on) - the Dzong on top of the demon’s stomach.
Today, The Dzong houses the head of Lama’s chamber, the Enemy Dzong (a chamber to store weapons), a storeroom, and the monastic school. 500 meters above the Dzong one can see the ruins of the Ta Dzong (watch tower). To the left of the Dzong, about 100 meters away is a water fortress (Chu Dzong) which today is used as a prayer hall for the students. In front of the Dzong, to the right is a crematorium. At the junction of the highway, there is a Chorten, which dates back to Zhabdrung’s time.