Dang is the most developed district and commercial center of Rapti zone. Originally the zonal capital used to be in Dang. Ghorahi and Tulsipur are the main commercial hubs for whole Rapti zone. Because it is located in relatively plain area, the transportation and the communication is much better comapring to other four districts of the zone.
Dang is divided in two parts called Dang and Deukhuri. Dang is the valley while Deukhuri is the Tarai region bordering India. Dang is also the most densly populated area in Rapti zone.
Rapti is a mid-western region of Nepal. It contains five districts: Dang, Rolpa, Rukum Salyan and Pyuthan. Headquarters: Tulsipur (Dang); largest town: Tribhuvannagar (Ghorahi).
Dang district comprises the inner Terai valleys Deukhuri and Dang plus parts of adjacent mountain rainges. The Deukhuri valley is separated from the Gangeatic Plains that begin at the Indian border by one branch of the low Siwalak range, and on the north by the other branch of the Siwalaks. The (West)Rapti River flows the length of Deukhuri after emerging from a gorge through the Mahabharat Range, eventually joining the Karnali River near Gorakhpur, India.
The Dang valley lies between the more northern branch of the Siwalaks and the much higher Mahabharat Range that is generally over 2,000 meters high, occasionally reaching 3,000 meters. Dang Valley is drained by the Babai river, another Karnali tributary.
Until a few decades ago both valleys were extremely malarial and virtually uninhabitable except to the Tharu ethnic group who seem to have evolved a degree of resistance. The government began using DDT to suppress the mosquito vectors, thus this relatively level fertile and well-watered land became useful to settlers from the hills who dispossessed and enslaved the Tharu by various stratagems.
Pyuthan, Rolpa and Salyan districts are situated in and north of the Mahabharat Range, in the so-called middle hills. Pyuthan district has extensive irrigated rice growing areas inhabited by Brahman-Chetri and Newar castes along Jimruk Khola, an upper tributary of the Rapti. Rolpa district mainly lies along Madi Khola, another upper Rapti tributary that is more eroded into an inner gorge and less useful for irrigation.