Maps of Middle Earth & Beleriand

I have a question on the maps of Middle Earth and beleriand. I ran across a map on some website which showed the entire lands of middle earth and placed beleriand just north of the lands in which the lord of the rings takes place. This map is the only i have seen of its kind and i was wondering if this was an actual map or just something that somone made up. I have always wondered where exactly Beleriand was in reference to Eriador, Arnor, Gondor, and all the others in LOTR. At the end of the silmarillion it says that after the war of wrath much of the land was destroyed or changed. does this mean that beleriand was no more or that it was changed into the likeness which we see commonly on maps in the LOTR?