The Lake of Vanished Armies is a long, narrow body of fresh water just outside the southeastern border of Sargava in the southern reaches of the Mwangi Expanse. The Korir River and the River of Lost Tears flow into the lake, and the Korir River flows out of it on its way to the sea at Port Freedom.
When the Chelish colonists first settled Sargava, they sent an expedition up the Korir River and found this deep lake. They judged it to be a perfect place for a settlement—but on the seventh night something emerged from the lake and took the entire force, leaving behind tents and gear. Two further expeditions to the lake met with the same fate. No more groups have been sent, and the secret of the lake remains undiscovered.
The lake and the rivers have soft, muddy banks making it difficult for large vessels to land. The locals pole rafts out to passing vessels in order to barter with their crews.
There are a number of small tribal settlements on the banks of the lake; the buildings are typically mud shacks. The inhabitants catch crabs and turtles and grow cereal crops. Elasmosauruses live in the lake, and tribal legends say that they are the offspring of Aomak, a mighty monster that lairs within the depths.