Thrimshing Gewog is located in southern part of the Dzongkhag with the maximum altitude of 2800m and minimum altitude of 1130m above the sea level. The Geog consists of 5 chiwogs with the total of 17 major villages. The Geog has a population of about approximately 6000 consisting of 615 households covering an area of approximately 55 square kilometers, bordering Lumang gewog from the west, Khaling Gewog from the North, Kangpara Gewog from the East and Gomdar Gewog under Samdrup Jongkhar Dzongkhags from the south.
The settlement is normally scattered and the geog is generally steep with deep gorges and narrow valleys. The geog has strong grass root level institutions like GT who is chaired by Gup and has representatives from almost all the villages called as Tshogpas.