Valley Fortress is the final fortress the player will have to face in Super Mario World. It can be accessed through a secret path from Valley of Bowser 2. It includes the castle obstacles that have logs with thorns on them, and the enemies Podoboo, Dry Bones, and Bony Beetle. The boss fight is with Reznors, which is like any other fortress in the game. Beating this level will make the player gain access to Back Door.
Like in all other Castles and Fortresses, the player will start off with a cutscene of the door opening into the fort. The player will be inside the fortress now. They will see the castle obstacles that have thorns on them, slamming in to the ground and rising up. The player can see a Green ! Block which will contain a Cape Feather. More of the castle obstacles can be seen, and now the player will see Spikes on the wall and the wall underneath it as well. Now the player will face a couple of Dry Bones, a Bony Beetle, and some Falling Spikes. More spikes and the thorn logs that slam into the ground can be seen. After the player passes this area, they will see lava, along with a ledge which has a Dry Bones along with a Yellow ! Block which will contain a Mushroom. Podoboos will pop out of the lava occasionally, so the player should advance cautiously. Another ledge with a Dry Bones, and another one with a Bony Beetle will be seen. The player will reach a ledge mounted on the ground, and see the thorn logs, which will move faster than before. The player must avoid them, while also jumping carefully along the pits of lavas filled with Podoboos. The player will see one last thorn log, which will go up instead of slamming down. The player will see the Boss Door, and will fight the Reznors. After the player defeats them, they will gain access to Back Door.