Gasa Dzong is the administrative headquarter of Gasa Dzongkhag. The Dzong was named after its protector Trashi Thongmoen. Legend believes that Zhabdrung, who was greeted by a deity of Gasa when he made his way to Bhutan gave the name of the deity. The Dzong was often called Gasa Dzong, which means “the land of Black Smith.” It refers to the Tekhungpa who was skilled in iron works and worked in the area.
Every year in the last week of the 10th month Bhutanese calendar, Drapai Loan (head of the lexicography division of the monastic body) led a contingent of monastic body to make the annual offerings to the deities. Gun salutation is performed on the 29th day to honor Mahakala.