List "MT On-Top-Of-The-World Peaks" By JerryBrekhus
Notes: Some peaks may be listed that do not actually qualify, especially those near the Canadian border. Also, this list could be incomplete.
Both Greathouse and Old Baldy are included, because the benchmark datasheet for Old Baldy gives 8681 ft for elevation, which is a tie with Greathouse. If they are indeed within a couple of feet of each other in elevation, standing on either one, you would see the other appear lower with a hand level.
Definition by Kai Xu:
"A mountain is 'on top of the world' (OTOTW) if no land rises above the horizon of an observer at its summit, considering that distant terrain dips below the horizon due to Earth’s curvature. The horizon is defined as the flat plane that intersects the summit and is perpendicular to the direction of gravity at the summit. 'Above the horizon' refers to the side of this plane opposite the direction of gravity."