The Terai is a plain landscape south of the outer foothills of the Himalaya, the Siwalik Hills, and north of the Indo-Gangetic Plain of the Ganges, Brahmaputra and their tributaries. This lowland belt is characterised by tall grasslands, scrub savannah, sal forests and clay rich swamps. In northern India, the Terai spreads eastward from the Yamuna River across Himachal Pradesh, Haryana, Uttarakhand, Uttar Pradesh and Bihar. The Terai is part the Terai-Duar savanna and grasslands ecoregion. Corresponding parts in West Bengal, Bangladesh, Bhutan and Assam east to the Brahmaputra River are called 'Dooars'. In Nepal, the Terai lies at an altitude of between and comprises more than 50 wetlands. North of the Terai rises the Bhabhar, a narrow but continuous belt of forest about wide.