About one week's sailing widdershins from the Counterweight continent. The natives speak a complex language and once worshipped an inn-sewer-ants polly-sea that fell from a high thermal into a bush from the smoking remains of Ankh-Morpork in The Colour of Magic. The strange (is anything strange when dealing with gods?) thing is that they have received surplus rainfall and a rich crop. The research team sent from Unseen University reported that "it only goes to show".
It is claimed that Llamedos Jones discovered the island (from a point of view of having had to travel from Llamedos to find them - the natives had already discovered them several millennia previously, but in the world of exploring that doesn't count) and there is in fact some supporting evidence that this may be the case.