ALDAN, a river of Siberia, in the government of Yakutsk, which rises about 55° N. lat., and 125° E. long., and after flowing more than 300 miles in a north-east direction, turns to the north-west, joining the Lena about 100 miles below Yakutsk. It has a total length of over 500 miles, for a considerable part of which it is navigable.

ALDAN MOUNTAINS, the name usually applied to a branch of the Stanovoi mountains, which strikes off from the main chain in the direction of the Aldan river, or to a part of this range. According to some geographers, however, the continuation of the Stanovoi range to Behring Strait, or even the whole mountain system of eastern Siberia, ought to receive the name.