Where can I find a map of Middle-earth during the Second Age circa SA 1600 (before the war of the Elves and Sauron)?
The following site (https://middle-earth.xenite.org/2013/01/09/do-any-maps-accurately-show-beleriand-and-eriador-together/) says:
The Second Age geography of Middle-earth prior to the Downfall of Númenor was different from the geography depicted by the Third Age map you see published in The Lord of the Rings. So far as I know, Tolkien never made an intermediate map, so we have no idea of what changes rendered by the War of Wrath were modified or wiped out by the Downfall of Númenor.