Hagen (1969) was among the earliest people to propose the physiographic subdivision of Nepal.
- Terai – Northern part of the Indo-Gangetic basin made up of Recent Alluvium spreading about 10-50 km in width.
- Churia Range (Siwaliks) or Sub-Himalaya and Dun Valleys – The Sub-Himalaya (Foreland basin) is made up of Siwalik or Churia Group of sedimentary rocks. The sediments from this subdivision cover the Dun Valleys and is also 10-50 km in width.
- Mahabharat range – is a 20-30 km width Lesser Himalayan unit made up of sedimentary, metamorphic and igneous rocks
- Midlands – is a 40-60 km wide Lesser Himalayan unit made up of sedimentary, metamorphic and igneous rocks with thrust sheets
- Fore Himalaya – Lesser and Higher Himalayan units spreading across 10-50 km width.
- Higher Himalaya and Inner Himalayan Valleys – Higher Himalayan unit is made up of high grade metamorphic rocks and also spreads across 10-50 km in width.
- Tibetan Marginal Range – The range consists of Tibetan or Tethys Himalayan unit made up of fossiliferous sedimentary rocks spreading across 10- 60 km width.