Cuiviénen (Quenya Tengwar: alUyT~V5$5; IPA: [kuɪviˈeːnen] or Third Age Middle-earth [kuɪviˈjeːnen]) is the land where the Quendi or Elves awoke. Its name (cuiviër+nen) means 'water of awakening,' and it is said to have been on the shore of a large gulf in the inland Sea of Helcar in the far east of Middle-earth. The Awakening of the Elves took place in very ancient times, during the Years of the Trees, and Cuiviénen is known to have been destroyed (perhaps by natural forces) since then.

The first Sundering of the Elves took place when the Eldar departed from Cuiviénen to Valinor, leaving behind the Avari who refused to leave.

It is unknown how long the Avari remained at Cuiviénen during the First Age, but it is certain that the Sea of Helcar ceased to exist after the War of Wrath, so "to Cuiviénen there is no returning".

Elven Realms of Middle-earth throughout the Ages
Years of the Trees:	Cuiviénen | Eglador | Havens of the Falas
First Age:	Doriath | Dorthonion | Gondolin | Havens of Sirion | Havens of the Falas | Himlad & Pass of Aglon | Hithlum | Maglor's Gap | March of Maedhros | Nargothrond | Nevrast | Ossiriand | Pass of Sirion | Thargelion
Second Age:	Eregion | Greenwood the Great | Lindon | Rivendell
Third Age:	Lindon | Lothlórien | Northern Mirkwood | Rivendell
Fourth Age:	Lindon | Lothlórien & East Lórien | Rivendell | Wood of Greenleaves