Lond Daer?
 

In some older maps, there is a city called 'Lond Daer' marked along the shores of the Greyflood river in Eriador. Does anyone know who founded it, what its history was, etc.? I know that the name means 'Havens of Shadow', or something to that effect.

You will find everything you could possibly want to know in Unfinished Tales - The History of Galadriel and Celeborn, Appendix D, which is entitled 'The Port of Lond Daer'. It was not a city, as such, but a former Numenorean harbour, established by Aldarion in the second age. As to the meaning of the name, Tolkien gave the translation as simply 'the Great Haven'.