Ossiriand

Lindon
J. R. R. Tolkien's legendarium location
Other name(s)	Ossiriand in the First Age Forlindon and Harlindon
Type	The Elvish lands west of the Blue Mountains that remained above the Sea after the drowning of Beleriand
Ruler	Gil-galad
First appearance	The Silmarillion, Unfinished Tales
Location	north-west Middle-earth
Lifespan	Founded S.A. 1
Founder	Gil-galad

Lindon is the land beyond the Ered Luin, the Blue Mountains, in the northwest of Middle-earth in the fictional universe of J. R. R. Tolkien. It is the westernmost land of the continent. The Gulf of Lune divides it into Forlindon (North Lindon) and Harlindon (South Lindon). Mithlond or the Grey Havens stood near the mouth of the River Lhûn at the gulf's eastern end.

Lindon serves as a narrative plot device, the final point of transition from the mortal changing world of Middle-earth to the unchanged Arda of the past.

Ossiriand (the 'Land of Seven Rivers'; cf. Q. otso, T. otos, S. odog, all meaning "seven") was the most eastern region of Beleriand during the First Age, lying between the Ered Luin and the river Gelion. Ossiriand was a green and forested land; Treebeard had fond memories of his summer visits to its elm-woods.

The Seven Rivers were, from north to south:

Along the northern side of the Ascar ran the Dwarf-road to Nogrod. North of Ossiriand lay the land of Thargelion, ruled by Caranthir son of Fëanor, and south of the river Adurant later lay the Land of the Dead that Live, where Lúthien and Beren lived their second lives.

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Wikipedia