Lothlórien (ca. 1350 S.A.)Lothlórien (ca. 1350 S.A.) - The founding of Lórien (which may mean "Golden Light") or Lothlórien ("Flower of Golden Light") is one of the least documented events in the history of Middle Earth, making its origin somewhat problematic.  It is known that Celeborn and Galadriel (the Lord and Lady of Lothlórien) traveled East with the company of Elves that founded Eregion.

 

"Celeborn and Galadriel therefore went eastwards, about the year 700 of the Second Age, and established the (primarily but by no means solely) Noldarin realm of Eregion." ~Unfinished Tales (The History of Galadriel and Celeborn)

 

But after awhile, they became too big for Eregion and decided to move on from there.

 

"...in the meantime the power of Galadriel and Celeborn had grown, and Galadriel, assisted in this by her friendship with the Dwarves of Moria, had come into contact with the Nandorin realm of Lórinand (Lórinand being the Nandorin name for Lothlórien) on the other side of the Misty Mountains" ~Unfinished Tales (The History of Galadriel and Celeborn)

 

The famous trees found in Lothlórien are the malinornë from Númenor, but originally coming from the Undying Lands (Tol Eressëa) making Lothlórien more like Valinor than any other realm in Middle Earth.

 

"...and some were given as a gift by Tar-Aldarion, the sixth King of Númenor (whose reign ended in 1075), to King Gil-galad of Lindon.  They did not take root in that land; but Gil-galad gave some to his kinswoman Galadriel, and under her power they grew and flourished in the guarded land of Lothlórien beside the River Anduin..." ~Unfinished Tales (A Description of Númenor)