Haa, the Mythic valley of the Guardian Spirit is bordered by Samtse to the southwest, Chhukha to the southeast and Paro Dzongkhag to the east, and by Tibet Autonomous Region of China in the North and is situated at an elevation ranging from 1000 to 5, 600 meters above sea level. The Dzongkhag is divided into six gewog. The total geographical area of the Dzongkhag is 1899.02 Sq.kms. It is one of the smallest districts in the country.
The fortress is located on 11 kilometers away from Chunzom towards proper Haa and was built in the 16th century by a Tibetan Lam Nawang Chogyal. The five storied fortress is perched on a hilltop and flanked by a hair-raising ravine descending to the basin of the Pachu-Wangchu. It was once one of the main centers of Drukpa Kagyudpa teachings, the state religion of the country. From the fortress one can view the lush green forests of Chhukha Dzongkhag with the highway running across it.
The construction of the Wangchulo Dzong was commissioned by Gongzim Ugyen Dorji, the Grandfather of the Royal Grandmother Ashi Kezang Choden Wangchuck. The Dzong structure resembles the Wangdicholing palace in Bumthang which was the seat of the 1st and 2nd Kings. It is a large square structure with battered (inward-sloping) walls.
Built by the Tibetan saint and king, Songtsen Gampo, Lhakhang Karpo with its sparkling white wall is situated at the foothills of the three towering mountains venerated as Rigsum Gonpo (Jampelyang:Manjushri, Chana Dorji: Vajrapani, Chenrizi: Avaloketesvara) it is located in the tiny village of Dumchoe. The temple stands as the guardian sentinels keeping watch at the south entrance of the Haa valley. According to a legend, a black and a white pigeon were released to select sites to build the temples. The white pigeon landed on the foothills of the mountain Chenrizi (Avaloketesvara), one of the towering Rigsum. Lhakhang Karpo was thus built on the foothills of the mountain Chenrizi (Avaloketesvara).
According to a legend, King Songtsen Gampo released a black and a white pigeon to select sites to build the temples. The white pigeon landed on the foothills of the mountain Chenrizi (Avaloketesvara) of the towering Rigsum. The black pigeon landed on a little north of the white pigeon, indicating the pre ordained site of the present day Lhakhang Nagpo.The temple was named Nagpo (black) as it was built on the site where the black pigeon landed.