The Nen River or Nenjiang (Chinese: 嫩江; pinyin: Nèn Jiāng; Wade–Giles: Nen-chiang), or Nonni (Manchu: ᠨᠣᠨ ᡠᠯᠠ, Möllendorff: non ula, Abkai: non ula) is a river in Northeast China.

The Nen River flows through the northern part of Heilongjiang Province and the northeastern section of Inner Mongolia, some parts of the river forming the border between the two regions.

Major tributaries of the Nen River include: During the Qing Dynasty the Nenjiang provided an important communication route between southern Manchuria and the cities of Qiqihar and Mergen, both of which served at various points as capitals of the Qing Heilongjiang.

A portage road connected the upper reaches of the Nenjiang with Aigun on the Amur as well.

[1] In November 1931, the bridge over the Nen River near Jiangqiao became the site of one of the first battles of the Second Sino-Japanese War.