The Orocarni was a mountain range in the far east made by the Valar before Arda was marred and the symmetry was lost in the wars against Melkor.
On the western slopes of the Orocarni grew the Wild Wood, and near a great waterfall of a river that flowed into the Inland Sea of Helcar the bay of Cuiviénen lay, where the Elves woke.
At their northern edge the Orocarni connected with the Ered Engrin, forming a situation much as the Ered Luin in the far west.
Four of the seven Fathers of the Dwarves awoke in the range.
After the end of the First Age the Orocarni remained, and it formed the eastern end of the land of Rhûn.
One of the rivers that arose in the Orocarni flowed into the inland Sea of Rhûn.
Because the Orocarni were far to the east, they were not visited by the Eldar, and the Edain did not reach them until the Fourth Age, the Orocarni do not appear in any of the tales of the Red Book of Westmarch.