South Island is divided into several regions known as "Zones", a common division on Earth. These Zones retain some political autonomy, though it is assumed the president has federal control. Most Zones conform to normal standards of South Island, electing mayors and other political officials. However, the monarchy has not been completely abolished, as displayed by places like Lake Zone, which has its own king.
Icecap Zone (possibly - it is unknown if the Icecap Zone in Eggman's Adventure is on South Island or Angel Island)