Board Thread:Manga/@comment-32365111-20170623002302/@comment-1327106-20170623003543

The walled country is on an island, Paradis. This is where all of the early story arcs take place. There were likely Titans running around the mainland at one point, and it appears that periodically they are intentionally unleashed (like in the attack on Fort Slava), but generally speaking the mainland seems to be Titan free.