Last Desert

At least according to Hobbit lore, in the distant east of Middle-earth lay a desert, the Last Desert, that was the abode of wild and fearsome creatures known as Were-worms.

It's unclear whether the Last Desert actually existed. Hobbit folklore was replete with tales of distant lands and dangerous creatures, such as the Mewlips or the immense 'turtle-fish' Fastitocalon, and it seems most likely that stories of the Last Desert with its Were-worms arose from tall tales rather than reality.

It should be noted, however, that some aspects of Hobbit tradition did seem to be rooted in the reality of Middle-earth. The journey to the home of the monstrous Mewlips, for instance, can be mapped with some likelihood onto known geography, while the Oliphaunt, long thought to be a creature belonging to fantastical tales, was in fact found to exist as the Mûmak of the far South. It's possible, then, that accounts of the Last Desert derive from near-forgotten cultural memories, or ancient travellers' tales, and that the desert itself - at least in some form - did actually exist in the remote East.