River, north-central China.
It rises in the mountains of southeastern Gansu province and flows east through Shaanxi province to join the Huang He (Yellow River). It is 537 mi (864 km) long. Its valley was the earliest centre of Chinese civilization and until the 10th century AD was the site of a succession of capital cities. In the 3rd century BC the area around the junction of the Ching and Wei rivers was the site of the first ambitious irrigation works in China.