The Kohenyu Graveyard is an area on the Floating Island completely isolated by a hazardous desert. The graveyard, actually a massive trench that spans a great distance, is home to the fallen skeletons of the Kohenyu, a race of dinosaur that existed on Mobius thousands of years ago before being hunted to extinction by the ancient Echidna tribe. Somewhere in the graveyard is an Emerald mine, hosting countless numbers of raw Emeralds ready to be shaped into Chaos Emeralds and to hold Chaos energy. The area in which these can be found is near the Soul Crystal, a collection of Emeralds that contains the soul of the Spirit of the Herd.
It was here that Knuckles the Echidna had to visit to collect a new Master Emerald after Doctor Zachary and one of the Guardian Robots destroyed the previous one. The visit didn't start well, with Knuckles failling prey to the poison dryalid plant that grows there. As the name suggests, the plant sprayed Knuckles with a toxic powder when he came too close. It was this that Knuckles blamed his "hallucinations" on, although it was actually the dead Kohenyu rising to enact their revenge. Knuckles fainted and was taken to the Emerald mine to be killed. Instead, Knuckles escaped to dig up a raw Emerald. He also threatened to destroy the memory of the Kohenyu forever by destroying the Soul Crystal, but spared them when he remembered what being alone was like. Knuckles left with the new Master Emerald, allowing the Kohenyu to return to their eternal slumber.
- The Graveyard is so treacherous that visitors are suggested to wear a gas mask and a poncho.
- The Emerald Mine hidden within is currently the target of the Drakon Empire, looking to put their Chaos energy in a vessel that can help them control the universe. This was stated as their new direction in The Betrayal of Mobius, when it was previously believed they only wanted to get the existing Chaos Emeralds.