Acherusia

In Greek mythology, Acherusia (Ancient Greek: 'Αχερουσια λιμνη or 'Αχερουσις) was a name given by the ancients to several lakes or swamps, which, like the various rivers called Acheron, were at some time believed to be connected with the underworld, until at last the Acherusia came to be considered to be in the lower world itself.