Arvernien
From the One Wiki to Rule Them All, the Lord of the Rings Encyclopedia.
The first rulers of the region of the Mouths of Sirion, known as Arvernien, were Tuor of the Edain and Idril of Gondolin. Later their son Eärendil Half-Elven, married the Half-Elven Elwing, Dior's daughter and survivor of the Sack of Doriath. Elros and Elrond, the sons of Eärendil and Elwing, were born in Arvernien.
