Dor Gyrth i chuinar was a land in southern Ossiriand so named by the Elves, where Beren and Lúthien dwelt after their return to life.
It was located around the river Adurant east of the Gelion, and was known for surrounding Tol Galen, where Beren and Lúthien lived again after being released from the Halls of Mandos until their final deaths.
History
Being a part of Ossiriand, this country was originally inhabited by the Nandor Elves and their later related brethren, the Laegeldrim, after the death of their lord Denethor in the First Battle of Beleriand. The extent of the Elven population was probably sparse and hidden at this time.
Some time around FA 469, having been granted a second but mortal life by Manwë under Eru, Beren and Lúthien returned to Middle-earth from the Halls of Mandos and settled on the isle of Tol Galen in southern Ossiriand. Thence the Eldar began to call the area Dor Gyrth i chuinar. News of their return spread amongst the Laiquendi, and the couple were regarded in high honour. Dior, the son of Beren and Lúthien was born in this country. After Beren recovered the Nauglamír and the Silmaril within it after the Battle of Sarn Athrad, it was said and sung that Lúthien wore it around her neck, and was therefore held as a great beauty in Middle-earth. Afterwards, the land became fair and beautiful, with a light and beauty like that seen only in Valinor, and apparently remained so until the final deaths of Beren and Lúthien and its destruction after the War of Wrath.
Etymology
Dor Gyrth i chuinar was a name in Sindarin that translated to "Land of the Dead that Live". The name contains the elements (n-)dôr ("land, dwelling-place"), the plural form of gorth ("dead; dead person"), i ("who, that"), and a nasal mutated plural form of cuina ("to be alive").
In other versions
The earliest forms of the name were I·Guilwarthon ("Living-dead") and I·Cuilwarthon ("Dead That Live Again") in Gnomish. Soon afterwards, Tolkien made a new variant: Cuilwarthien ("Land of the Dead that Live"). Some time later, he changed the name to Gwerth-i-cuina ("Living Dead" or "Land of the Dead that Live"). A variation of this was Gwerth-i-guinar ("Dead that Live").
In the published version of The Silmarillion, Dor Gyrth i chuinar appears written as Dor Firn-i-Guinar, a name included also in The Etymologies in The Lost Road and Other Writings.
Tolkien changed the name finally to Dor Gyrth i chuinar in 1972, in a reference to the death of his wife, Edith Tolkien.