Thargelion

J. R. R. Tolkien's Middle-earth legendarium contains many locations. Some of the minor places in the region of Beleriand during the First Age are described below. It is to be supposed that all of them were destroyed in the Drowning of Beleriand during the War of Wrath unless otherwise noted.

(for the city of Gondor see Minas Tirith)

A tower on the island of Tol Sirion that guarded the Pass of Sirion. Minas Tirith was built early in the First Age by Finrod to keep watch upon the doings of Morgoth on the northern plain of Ard-galen and prevent passage south by Orcs through the Pass of Sirion, the West Gate of Beleriand. It was under the command of Finrod's brother Orodreth.

In 457 First Age it was stormed and taken by Sauron. Sauron, then also known as Gorthaur, made it a place of such terror and horror it was renamed Tol-in-Gaurhoth, the Isle of Werewolves.

...
Wikipedia