The Himalayan range is commonly classified into three regions: the Eastern Himalaya (Sikkim-Darjeeling, Bhutan, Arunachal Pradesh), Central Himalaya (Uttarakhand, Nepal) and Western Himalaya (Kashmir, Himachal Pradesh). When travelling through the Himalaya from south to north, there are differences in the stratigraphy and structure between the Sub-, Lesser, Greater/Higher and Tethyan Himalaya subdivisions. However, there is a great deal of resemblance between the same along its strike elongation in different subdivisions. To illustrate its location within the broad Himalayan range, a geological entity of Darjeeling-Sikkim Himalaya (DSH) is required. The South Tibetan Detachment System (STDS), the MCT (Main Central Thrust), the MBT (Main Boundary Thrust) and the MFT (Main Frontal Thrust) against the Quaternary Indo-Gangetic alluvium are, in a nutshell, the main structural components in the DSH, arranged from north to south. Naturally, there is also another push called the Ramgarh push that divides the Gondwanas from the metamorphics to the north. The MCT delineates the boundary between the Lesser Himalayan Sequence (LHS) and the Higher Himalayan Crystallines (HHC), just like other regions do. The MBT divides the Siwaliks from the Dalings and the northern Gondwanas in the Teesta valley region, where the MFT is reported not to be exposed. This chapter discusses the unique geographical uniqueness of the region, which goes beyond its geological view. An outline of the DSH is given here, covering Early History, People, Administrative Division, Communication, Climate, Flora and Fauna.