The Seymchan (Russian: Сеймчан) is a river in Srednekansky District, Magadan Oblast, Russia.

It is a left tributary of the Kolyma, with a length of 158 kilometres (98 mi) a drainage basin of 3,600 square kilometres (1,400 sq mi).

[1][2] The name comes from the Yakut language word Kheymchen, which is an area of open water surrounded by sea ice.

[3] The river rises in the Upper Kolyma Highlands, eastern limits of the Chersky Range, at the confluence of Left Seymchan and Right Seymchan.

[4] Together with the Buyunda that flows roughly northwards on the other side of the Kolyma basin, the Seymchan forms the Seymchan-Buyunda Depression, which limits the Upper Kolyma Highlands from the east.