The present place where the Dzongs stands is the limit between basic to three western locales: Sha wangduephodrang, Wing Thimphu and Pa Paro.
The crossing point was set apart with three stones that have a place with the general population of Punakha, Thimphu, and Paro.
Encompassed by these three stones was a land parcel known as Sem-tokha or Sem-dokha with a sanctuary based on it. This sanctuary was later talented to Zhabdrung by Lama Pangka Shong.
History says that a Tibetan Lama Zhang has forecasted that Zhabdrung Ngawang Namgyel would fabricate a Dzong at the intersection of three western grounds. To satisfy the prediction and respect the offer of Lama Panka Shons, Zhbdrung chose to assemble the Dzong.
The region was possessed by numerous evil spirits, and legend has it that the site where Zhabdrung chose to fabricate the Dzong was involved by a devil that would hurt explorers who frequently remained amid the night.
Zhabdrung went by the place and repressed the evil spirit, banishing her into the stone on the slope where the present Dzong is found.
The Dzong was developed encasing the stone, to guarantee the proceeding with detainment of the evil spirit. Henceforth the dzong inferred its name as Simtokha, from the word sunmo devil, do stomach and kha on - the Dzong over the evil spirit's stomach.