Anórien is a region and fiefdom of Gondor, called Sunlending by the Rohirrim. The name does not refer to the West but is 'heraldic', related to the name and the emblem of Anárion, son of Elendil: the land is immediately attached to the Minas Anor.
During the Elder Days, Anórien was occupied by Pre-Númenórean Men.  These were separated relatives of the House of Haleth while the Edain migrated to the west during the First Age. The Woses fled to the forests of that region, hunted by the Men of Darkness
During the War of the Ring, when Sauron released a secondary force from the Morannon. They overwhelmed the defenders of Cair Andros, and used the island to cross into Anórien. They blocked the eastward progress of the Rohirrim as they rode to Gondor's aid, though after the Battle of the Pelennor Fields, the Rohirrim chased them down and pushed them back out of Anórien.
Anórien lay north of Minas Tirith and the line of the White Mountains, and was the only part of the northern half of the realm, Calenardhon, which was not given to the Éothéod to become the Kingdom of Rohan.
Anórien formed a narrow strip of land consisting of the valleys of the White Mountains, and its borders were the Mering Stream in the west, and the Mouths of the Entwash in the north. Its eastern border was the border of Gondor at the Anduin.
The Greenway road traversed the fief.
The name is purely heraldic and doesn't refer to its climate or sunshine.
- ↑ 1.0 1.1 J.R.R. Tolkien, "Nomenclature of The Lord of the Rings" in Wayne G. Hammond and Christina Scull (eds), The Lord of the Rings: A Reader's Companion, p. 776
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), Unfinished Tales, "Cirion and Eorl and the Friendship of Gondor and Rohan"
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), Unfinished Tales, "The Drúedain"
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), The Peoples of Middle-earth, "The Heirs of Elendil"