The Dori, also called Lora and Kadanai is a river of Afghanistan and Pakistan. It is a tributary of the Arghandab River and sub tributary of the Helmand River and runs for 320 kilometres through Kandahar Province in Afghanistan and Balochistan in Pakistan.
The Dori begins north of the city of Quetta. It is called Lora in its headwaters in Pakistan. The name changes to Kadanai upon its entry into Afghanistan, and the name Dori is given below the town of Spin Baldak.
In Afghanistan, Dori first runs westward and soon faces the sandy desert of Rigestan. It then takes a northerly direction and along the desert passes east and northeast past Takht-e Pol, bordering southeast of the Kandahar Valley. Shortly after, it receives the Arghastan River and then the Tarnak River, both on the left bank, some thirty kilometers south of the city of Kandahar.
The Dori receives most of its flow from melting snow in spring, especially in March.
Irrigation greatly reduces its speed. At Takht-e Pol it amounts to more or less than 1 m per second.