Inland Sea

A vast landlocked body of water that lay in the East of Middle-earth, and was commonly called the Sea of Rhûn. Fed by the waters of the River Celduin, at its widest the Inland Sea was some one hundred and fifty miles across. It held a large forested island, and the northeastern coasts of the Sea were also densely forested. To the southwest stood a range of hills rising up from the shoreline.

Note that the geographic term 'inland sea' is occasionally used for the rather smaller Sea of Núrnen in Mordor, which lay far to the south and west of the Sea of Rhûn. As a capitalised place-name, however, 'Inland Sea' is always a reference to the Sea of Rhûn rather than Núrnen.