UL'dah's sister city Sihl'da!?

[Arcell]

Correct. You're referring to Thavnair and its capital city of Radz-at-Han, which is to the east, across the Sea of Jade. There's also Meracydia to the south, across the Sea of Ash, which is apparently a very tribal region, with heavy voodoo influences.

(Copied from my post here)

Not to mention Limsa's own Admiral discovered a route to the western continent across the Indigo Deep.

http://static.finalfantasyxiv.com/pl...001.png?_v=732