⛰️Mountains of the East!

[Kahmûl]

East of the Iron Hills are the Mountains of th east and the sea of Helcar but after the war of wrath were they separated from Middle Earth?

 

[gate7ole]

Now this is a tough question. I don't remember reading somewhere that the Orocarni (Mts of East) were separated from the great continent of ME, but I have the impression that Helcar no longer exists, mostly judging by the following quote from Silmarillion:

and to Cuiviénen there is no returning.

Now, I'm sure some more info can be found in HOME. I will search when I find some time. (or if someone else does it first).

 

[gate7ole]

HOME I
And the Earth was again broken in the second battle, when Melko was again overthrown, and it has changed ever in the wearing and passing of many ages.' But the greatest change took place, when the First Design was destroyed, and the Earth was rounded, and severed from Valinor. This befell in the days of the assault of the Numenoreans upon the land of the Gods, as is told in the Histories. And since that time the world has forgotten the things that were before, and the names and the memory of the lands and waters of old has perished.

HOME XI
(about Cuiviénen). In the texts of the post-Lord of the Rings period there is the statement in the Grey Annals that it was 'in the midmost regions of the world', as in the emended reading of AV 2; and there is the new phrase in the revision of QS, 'in the midmost parts of Middle-earth beyond the Great River and the Inner Sea' (with loss of the mention in the original text of 'the eastern sea'). This last shows unambiguously that a change had taken place, but it is very hard to say what it was. It cannot be made to agree with the old Ambarkanta maps: one might indeed doubt that those maps carried much validity for the eastern regions by this time, and wonder whether by 'the Inner Sea' my father was referring to 'the Inland Sea of Rhun' (see The Treason of Isengard pp. 307, 333) - but on the other hand, in the Annals of Aman (X.72, 82) from this same period the Great Journey of the Elves from Kuivienen ('a bay in the Inland Sea of Helkar') is described in terms that suggest that the old conception was still fully present. Can the Sea of Rhun be identified with the Sea of Helkar, vastly shrunken?

The two quotes may not bring much light to the topic, but I couldn’t find anything else about the matter in the HOME books. But the first quote certainly implies that Helkar and Orocarni were much altered during the Downfall of Númenor, while the second discusses the subject of the position of Helkar (with a possible explanation that it is the sea of Rhun).