In The Adventure of Link, Moruge Swamp is a swamp situated directly to the north of the Water Town of Saria. To get to the swamp, Link must first obtain the Jump Spell from the Town of Ruto, and then pass through the cave south of the town. The swamp borders a mountain range to the north, and a cave blocked by a boulder can be found where it borders said mountain range. By opening the cave using the Hammer found in Death Mountain, Link will be able to enter the cave infested with Daira. It is at the end of the cave that the young hero finds the Water of Life, which he gives to the mother of a sick girl in the Harbor Town of Mido to receive the Fairy Spell from an Old Man. A 1-Up Link Doll and a Fairy can also be found around the swamp.
Link has to cross its motion-inhibiting mire on his way to the Water Town of Saria during his quest to wake Princess Zelda.
The following section is not part of the Zelda canon and should not be taken as such.
The Crystal Trap
In The Crystal Trap, the Moruge Swamp (misspelled as "Moluge") is briefly mentioned when Princess Zelda reaches the Pillar Crossroads and is trying to pick which way to go, whether through the Desert, Swamp, or the Forest. The Swamp, however, is never confirmed to be the Moruge Swamp.[2]
The Shadow Prince
Although Moruge Swamp isn't visited in The Shadow Prince, it is mentioned by Link as he tries to decide whether he should take the safe route of the Ruto Town detour and go through Moruge Swamp or if he should go through the short but dangerous Midoro Swamp path.[3] Even if he does choose to go through Ruto, his passage through the Moruge Swamp is never mentioned in the book.
↑Encyclopedia, Dark Horse Books, pg. 224 (TAoLThe Adventure of Link)
↑And that's a carving of a swamp. But which swamp, Midoro or Moluge? (The Crystal Trap, Simon & Schuster, pg. 30)
↑'Hmm,' he says. 'Maybe I should bypass the swamp and go west, by Ruto Town. Of course, there's still Moruge Swamp to the south of Ruto, but that's safer than Midoro. (The Shadow Prince, Simon & Schuster, pg. 111)