The river begins at the confluence of the rivers Sartang and Dulgalakh. It flows north across the vast Yana-Indigirka Lowland, part of the greater East Siberian Lowland, shared with the Indigirka to the east. As the river flows into the Yana Bay of the Laptev Sea, it forms a huge river delta covering 10,200 square kilometres (3,900 sq mi).[3] Yarok is a large flat island located east of the main mouths of the Yana.