渭河是黄河的第一大支流，发源于中国甘肃省渭源县的鸟鼠山，由陕西省潼关汇入黄河。渭河全长818公里，流域包括甘肃、宁夏、陕西三省区，总面积134766平方公里，其中陕西占50%，甘肃占44%。

渭河上游以及北岸泾河、洛河等支流，流经黄土高原，携带大量泥沙。

渭河流域的东部为渭河平原区；西部为黄土丘陵沟壑区。

导入渭河的河流有葫芦河、清姜河、麦李河、石头河、泾河、洛河。

中国古代历代为了灌溉和水运的目的，修筑了渠道。公元前246年，秦朝的郑国渠引泾河到洛河、漕渠，汉武帝时的白公渠引泾河到渭河、泾惠渠、渭惠渠、洛惠渠等水道，这些渠道主要集中在渭河的中下游。

The Wei River (Chinese:渭河; pinyin:Wèi Hé; Wade–Giles:Wei Ho) is a major river in west-central China's Gansu and Shaanxi provinces. It is the largest tributary of the Yellow River and very important in the early development of Chinese civilization.

The source of the Wei River is close to Weiyuan County –Wei yuan meaning "Wei's source" –in Gansu province, less than 200 kilometres (120 mi) from the Yellow River at Lanzhou. However, due to the sharp turn north the Yellow River takes in Lanzhou, the Wei and the Yellow River do not meet for more than 2,000 kilometres (1,200 mi) further along the Yellow River's course. In a direct line, the Wei's source lies 700 kilometres (430 mi) west of the main city along its course, Xi'an in Shaanxi province. The length of the river is 818 kilometres (508 mi) and the area drained covers 135,000 square kilometres (52,000 sq mi).