Feral Heart

I am sorry if this question has been answered but I haven't been able to find it. I have downloaded maps and as many of you know, maps contain many things that go with them to make them open for use. The trouble is that my computer gets over crowded with space and maps take up a big part of it. Some of these maps I want to fully delete but I don't know how. I am on a Mac and I have only figured out how to stop the main map from existing, so the portal to the map still exist but when I go inside the portal the map is all black so it still exist. Is there a way to totally delete it?