Tirin na Gilweth was the great tower of Kortirion according to the early version of the legendarium in The Book of Lost Tales. It was built by Ingil son of Inwë after his return to Tol Eressëa following the March of Liberation.
The tower was described as being "tall and grey", and Kortirion itself was named after it.
At the foot of the tower was the dwelling of Meril-i-Turinqi, the Lady of Tol Eressëa, amidst a korin of elms.