|This location exists primarily or exclusively within the Pre-Super Genesis Wave continuity.|
Information in this article may not be canonical to the storyline of the games or any other Sonic continuity.
Mount Osohai was a massive peak surrounded by jagged rock spikes for foothills, and as such it had never been ascended.
A Chaos Emerald fragment crashed into Mount Osohai after the original gem was split in two by Dr. Robotnik, making Knuckles the Echidna go investigate the mountain. The Emerald fragment began burrowing through the rock to reach Angel Island's sole Chaos Emerald, and the mountain began shaking and dropped a rock that knocked Knuckles unconscious, though he was fortunately saved by the Ancient Walkers.
- Mount Osohai's name may be a pun on the term "oh so high".