The Swamp Palace is the second dungeon in the Dark World, and the sixth overall, in The Legend of Zelda: A Link to the Past. It is located in the Great Swamp, west of Lake Hylia, where its Light World parallel is also found.
On his quest to free the Seven Maidens, Link enters the Swamp Palace. However, he finds that the ladder leading into the main dungeon has broken off. Sahasrahla contacts Link by means of a Telepathic Tile and informs him that certain changes made in the Light World will also cause change to happen in the Dark World. Link uses the Magic Mirror to travel to the Light World and enters the Swamp Ruins. Inside, he drains the water, effectively causing water to fill the Swamp Palace in the Dark World. Link uses the water to circumvent the broken ladder and traverses the dungeon. After defeating Arrghus, Link rescues the second Maiden.
Many of the puzzles in the Swamp Palace revolve around raising and lowering the water level inside the palace, using many switches placed in the dungeon.