The Alwand or Halwan River (Arabic: نهر حلوان, Southern Kurdish: چەم ئەڵوەن, Persian: رود الوند) is a river in eastern Iraq and western Iran. It rises in the Zagros Mountains in Iran.
The river flows west from the mountains to the city of Qasr-e Shirin, where it turns south and crosses the border with Iraq. It then divides the city of Khanaqin in two parts. It has played a significant role in land cultivation and in establishment of a strong rural society in the area, and is considered by the people of Khanaqin as a symbol for their unity and Kurdish identity.
The river joins the Diyala River at Zengabadh.