|Where||Mine, below the Forest|
|Opened||January 22, 2010|
The Hidden Lake is a room in Club Penguin which is opened for all penguins. It was first opened in the Cave Expedition where you needed to have the Amethyst Pin to come in here. It re-opened on March 15, 2010, where you didn't need any items to get in.
On the right side of the Hidden Lake, there is a door to the Underwater Room, which is open only to members, who find the key to that room. As of the Island Adventure Party 2010, there is a permanent entrance to the Hidden Lake from the Forest, making it not really "hidden" anymore.
Due to tremors in 2013, the path to the Gold Mine was closed on November 7, 2013.
- It is not decorated for many parties, as it already looks like it's decorated.
- There is a broken Aqua Grabber resting in the bottom left corner.
- The Crabs Talk To Crabs mini game was located here during the Island Adventure Party 2011.
- During the Cave Expedition, there was a catalog for members.
- At the Island Adventure Party 2010, it turned into a Mermaid's Cove.
- During the Celebration of Water 2010, it was filled up with water, and since penguins were underwater they could walk on walls, but only up to the water tank at the surface.
- At some parties, the entrance to the Forest is blocked off.
- Prior to Operation: Puffle, and after November 2013 Tremors, the path to Gold Mine was blocked by huge lumps of brownish rocks.
- Candy Apple Pin
- Red Puffle Pin
- Red Electric Guitar Pin
- Crystal Ball Pin
- Dub-step Puffle pin
- Elemental Pin
- Coconut Smoothie Pin
- Pixel Puffle Pin
- Orange Slice Pin