Tolfalas was a large island, claimed by Gondor and located in the Bay of Belfalas just beyond the Mouths of Anduin, between Belfalas and Harondor.

The present shape and location of Tolfalas (sometimes referred to as Tol Falas) was the result of the two greatest disasters to befall Middle-earth. During the First Age, Tolfalas was a part of the mainland, but the rising of the waters of Belagaer after the destruction of Beleriand sundered it from the mainland.

Tolfalas then became its current shape when the seas invaded the coastlands at the Drowning of Númenor in SA 3319, and all the seaward regions of the west of Middle-earth were changed.