阿尔丹河(俄语：Алдан)位于西伯利亚东部，是勒拿河第二长的支流，全长2,273公里，其中1,600公里可通航。流域面积729 000平方公里，平均流量5060立方公尺/秒。

发源于外兴安岭西南。向东北流过阿尔丹、Ust'-Maya、El'dikan 和 Khandyga，然后转向西北，在 Batamay 附近注入勒拿河。

本河主要支流有Амга、Uchur 和 Maya。流域盛产金和寒武纪化石。

The Aldan River (Russian:Алдан) is the second-longest tributary of the Lena River in the Sakha Republic in eastern Siberia. The river is 2,273 kilometres (1,412 mi) long, of which around 1,600 kilometres (990 mi) is navigable. It was part of the River Route to Okhotsk. In 1639 Ivan Moskvitin ascended the Aldan and Maya Rivers and crossed to the Ulya River to reach the Sea of Okhotsk.