Argonnessen is continent to the far east of Khorvaire and south of Sarlona. The continent of Argonnessen is almost totally unexplored by any race of Khorvaire due to the fact that it is inhabited primarily by Dragons. The continent went to war with Aerenal and destroyed the Giant civilization.
Off of Argonnessen lies the island of Seren. Argonnessen (and Seren) are for the most part off limits to the "lesser races" (which includes almost everyone except a dragon). The continent and island are also inhabited by dragon-worshipping human barbarians. Many of the continent's dragons are members of a group known as the Chamber, which interprets the Draconic Prophecy and uses it to shape the world to the dragons' liking.