The Merchimden (Russian: Мерчимден) is a river in Yakutia (Sakha Republic), Russia.

[1] The river flows north of the Arctic Circle across a lonely, desolate area of Olenyoksky District devoid of settlements.

[2] The Merchimden originates in the eastern fringes of the Central Siberian Plateau, very near the sources of the east-flowing Motorchuna.

Finally it meets the right bank of the Olenyok 539 km (335 mi) from its mouth.

[3] The river is frozen between the first half of October and early June.