The Khudan (Russian: Худан, also: Худун, Кудун, Кодун)[1] is a river in Buryatia, southern East Siberia, Russia.

The Khudan is a left tributary of the Uda, of the Selenga basin.

The river has its sources in the Khudan Range by the junction with the Tsagan-Khurtei range, 5 km (3.1 mi) to the northwest of 1,554 m (5,098 ft) high Mount Khudan, about 120 km (75 mi) west of Chita.

The Khudan flows roughly in a WNW direction and meets the Uda 200 kilometres (120 mi) from its mouth in the Selenga.

[3] The river is generally frozen from mid-October or early November until April or May.