Coordinates: 23°26′24″N 121°21′43″E / 23.439959°N 121.362076°E
The Huatung Valley or Hualien-Taitung Valley (Chinese: 花東縱谷; pinyin: Huādōng Zònggǔ; Wade–Giles: Hua1-tung1 Tsung4-ku3), also known as East Rift Valley or the Longitudinal Valley, is a long and narrow valley located at the between Chungyang Range and Haian Range. It is also recognized as a plain area which stretches for about 180 kilometers near the eastern coast of Taiwan, passes from the Hualien City at the north to the Taitung City at the south. It was called Nakasendō Plain (中仙道平野 Nakasendō heiya?) or Nakasendō during era of Japanese rule.
The valley is believed to be part of the northern terminus of the Philippine Mobile Belt, a complex collection of tectonic plate fragments and volcanic intrusions.