鄂尔浑省 (Орхон аймаг)位于蒙古国北部，面积840平方公里，人口71,525 (2000年)。首府额尔登特。

得名于流经该省的鄂尔浑河。鄂尔浑峡谷文化景观一部份在本省。

Orkhon Aimag (Mongolian:Орхон аймаг) is one of the 21 Aimags (provinces) of Mongolia, located in the north of the country. Its capital is Erdenet. The province is named after Orkhon River. This Aimag was cut out of Bulgan Aimag in 1994, to form a new entity together with its capital Erdenet, which had previously been administrated as a federal municipality.