Forty Fathoms

The Forty Fathoms are a sea stretching from the southern islands of the Acorn Archipelago in the west to Tralius in the east. Named for their shallow depth, the Fathoms are often considered the border between the two great oceans of Sonic's World, with the Northern Ocean to the north of the Fathoms and the Southern Ocean to the south.

History
The Fathoms are home to historically important shipping routes between Yurashia, Downunda and the Kingdom of Mobius. During Dr. Robotnik's uprising against the Kingdom of Mobius, the Forty Fathoms came under the control of the Eggman Empire, with Octobot as their regional leader.

Octobot was overthrown by the Forty Fathoms Freedom Fighters concurrently with the overthrow of Downunda's Dundee Croc and subsequently became part of the new Downunder nation.