Tolfalas
From Tolkien Gateway
Tolfalas was a large island, also named in the form Tol Falas, that stood beyond the Ethir Anduin in the Bay of Belfalas.
During the Drowning of Númenor Tolfalas was almost destroyed, and was left like a barren and lonely mountain in the water not far from the Ethir.[1]
Its sharp southern cape was traditionally considered as marking the southernmost point of Gondor proper.