Lond Daer

We don't know the exact date that Aldarion established this haven at the mouth of Gwathló, but we do know that it was on a voyage to Middle-earth immediately preceding his formal recognition as King's Heir of Númenor. That declaration took place in II 800, so the haven of Vinyalondë (which would become Lond Daer) must have built a few years before that date.

Lond Daer appears on maps of Middle-earth from the end of the Third Age, so it must have survived in some form until then. At that time it would have existed for nearly six thousand years, and with no Dúnedain to maintain the haven, it was likely little more than a ruin by that time. Indeed, Tolkien's original label for Lond Daer when it was added to the map of Middle-earth (as described in a footnote in Unfinished Tales) was 'Lond Daer (ruins)'.

The name Lond Daer seems to have emerged as a shortening of Lond Daer Enedh, 'Great Middle Haven'. This name originated in the later Second Age, after the establishment of the port of Pelargir on Anduin in II 2350. After this time, Lond Daer was the 'Great Middle Haven' between Pelargir in the south and havens of Lindon far to the north.