Darjeeling Himalayan hill region or Darjeeling Himalaya is the mountainous area on the north-western side of the state of West Bengal in India. This region belongs to the Eastern Himalaya range. The Darjeeling district except the Siliguri subdivision and the entire Kalimpong district constitute this region. It arises abruptly from the Terai region. The region slopes from a south to north direction. The river Teesta divides the region in two parts — the region to the east of Teesta and the region to the west of Teesta.