Morang District is located in Koshi Province in eastern Nepal. It is an Outer Terai district, which borders Jhapa to the east, Dhankuta and Panchthar to the north, Sunsari to the west, and Bihar, India, to the south. Morang has one metropolitan city (Biratnagar), eight municipalities and eight rural municipalities. The total area of the district is 1,855 km2 (716 sq mi). The lowest elevation point is 60 meters and the highest is 2,410 meters above sea level. The headquarters of Morang is connected by the Koshi National Highway to the east–west Mahendra National Highway at Itahari, Sunsari. Morang is also connected to the Hill parts of the eastern region of Nepal. Morang is the core industrial sector for the eastern region of Nepal.

The Terai or Tarai is to a lowland region in parts of northern India and southern Nepal that lies to the south of the outer foothills of the Himalayas, the Sivalik Hills and north of the Indo-Gangetic Plain. This lowland belt is characterised by tall grasslands, scrub savannah, sal forests and clay rich swamps. In North India, the Terai spreads from the Yamuna River eastward across Haryana, Uttarakhand, Uttar Pradesh, Bihar and West Bengal. The Terai is part of the Terai-Duar savanna and grasslands ecoregion. Nepal's Terai stretches over 33,998.8 km2 (13,127.0 sq mi), about 23.1% of Nepal's land area, and lies at an elevation of between 67 and 300 m. The region comprises more than 50 wetlands. North of the Terai rises the Bhabar, a narrow but continuous belt of forest about 8–12 km (5.0–7.5 mi) wide.