Maze Island
From Zelda Wiki.org
Maze Island is a rather large island in Hyrule that, like its name suggests, is a natural labyrinth.
Narrow passageways lined by unclimbable rock walls, impassable rivers with only the occasional bridge across them, and hidden pitfalls make traveling on this island both dangerous and time-consuming.
Maze Island's single most famous landmark is the Maze Island Palace, which Link visited during his quest to wake the sleeping Princess Zelda.
Maze Island is also the name of an island in Phantom Hourglass. It is unknown if they are related.
Phantom Hourglass
In The Phantom Hourglass, Maze Island can be found in the Northeastern Sea, however it is initially unmarked. It contains three increasingly difficult mazes: Beginner, Normal and Expert. For each you successfully complete within the time limit, you gain a prize. Completing the Beginner difficulty gets you a Wisdom Gem, and finishing the Normal difficulty nets you a Treasure Map. Only by completing Expert will the island relinquish its Heart Container.

