Land of Ice

The Northern Continent is where all of the world's worst criminals were sent. It is presumably near the North Pole, as 500 years ago, Oars froze to death there, due to wearing nothing but a loincloth. His frostbitten corpse was later found by Gekko Moriah.

Trivia

 * It was said that this is where the world's worst criminals were sent, which contradicts the purpose of Impel Down, although this may be due to Impel Down not being built 500 years ago.