Aldan River
Yakutsk-Udsk Track: This was an ill-defined route used to supply Udsk from Yakutsk. It was open from April to October but there was some winter travel. Its length was estimated at . It crossed the Amga River at Amginsk, the Aldan River at Kompaneisk and the Uchur River at Uchur Crossing. Pack horses were usually left at Udsk as food for sled dogs or people while the Yakut drivers returned to Yakutsk on foot or skis. In 1750 all the pack horses perished in deep snow resulting in starvation. In 1788 more than 100 horses drowned during the spring snowmelt.