Lake Eridanus is a large body of water at the junction of of the nations of T'Nanshi and Ferrell. The independent city of Elysia is on its eastern shore, and Ferrell's Port Eridanus is on the northwest.
The lake is between 5 miles and 10 miles across. It is connected to the sea to the south by the Eridanian River. Both the river and the lake are wide enough for ships to pass through, and are major inland shipping lanes.
A popular fishing spot, many Ferrell trout are pulled from its shores.