The Falathrim were the shoreland Elves of the Falas who took Círdan as their lord from the beginning. Their last home on Middle-earth before finally leaving for the Undying Lands was the Grey Havens, but before that they dwelt mainly in the ancient havens of Eglarest and Brithombar.
Of Telerin descent, these Elves remained in Beleriand when their kin journeyed to Valinor at the persuasion of the Maia Ossë. They were the second of two "subdivisions" of the Teleri to stay behind, the other being the Eglath, who stayed behind to find their lost lord Elwë.
The Elves of the Havens enjoyed peaceful relations with all the Elves of Beleriand, and were particularly closely allied with the people of Nargothrond. As one of the most remote peoples from Morgoth's forces in Angband, the other Elvish lords would often send their children to the Elves of the Havens for safekeeping.
After the Nirnaeth Arnoediad, Brithombar and Eglarest were besieged and taken by Morgoth's armies, and most of the Elves were slain or imprisoned. Some few, including Círdan and the young Ereinion Gil-galad, who was at that time lodging with the people of the Havens, sailed south to safety on the Isle of Balar.
Another name for the Falathrim was the Egladhrim, or the Eglain, a Sindarin name meaning "The Forsaken". While originally used as a name for the Sindar by themselves, it came to refer only to the Elves of the Falas, as distinguished from the "inland Elves" of Beleriand.