The mountain whose peak is furthest from the center of the Earth is Mount Chimborazo in Ecuador.

While Mount Everest is the highest mountain above sea level, the Earth is an oblate spheroid, meaning it bulges at the equator. Chimborazo, located closer to the equator, sits on a point where the Earth's bulge is more pronounced. This means its peak, though lower than Everest in terms of elevation, is actually further from the Earth's center.